Architect of Worlds – Step Seventeen: Determine Obliquity

September 14, 2020 Sharrukin Comments 2 comments

The obliquity of an object is the angle between its rotational axis and its orbital axis, or equivalently the angle between its equatorial plane and its orbital plane. It’s often colloquially called the axial tilt of a moon or planet. Obliquity can have significant effects on the surface conditions of a world, affecting daily and seasonal variations in temperature.

Procedure

Begin by noting the situation the world being developed is in: is it a major satellite of a planet, a planet with its own major satellite, or a planet without any major satellite? Notice that these three cases exactly parallel those in Step Sixteen.

First Case: Major Satellites of Planets

Major satellites of planets, as placed in Step Fourteen, will tend to have little or no obliquity with respect to the planet’s orbital plane. To determine the obliquity of such a satellite at random, roll 3d6-8 (minimum 0) and take the result as the obliquity in degrees.

Note that the major satellites of gas giants, distant from their primary star, may be an exception to this general rule. For example, in our own planetary system, the planet Uranus is tilted at almost 90 degrees to its orbital plane. Its satellites all orbit close to the equatorial plane of Uranus, so their orbits are also at a large angle, and their obliquity is very high. Cases like this are very unlikely for the smaller planets close to a primary star – tidal interactions will tend to quickly “flatten” the orbital planes of any major satellites there.

Second Case: Planets with Major Satellites

A Leftover Oligarch, Terrestrial Planet, or Failed Core which has a major satellite is likely to have its obliquity stabilized by the presence of that satellite.

To select a value of the planet’s obliquity at random, roll 3d6. Add the same modifier that was computed during Step Sixteen for the Rotation Period Table, based on the degree of tidal deceleration applied by the major satellite. Refer to the Obliquity Table.

Obliquity Table
Modified Roll	Obliquity
4 or less	Extreme (see Extreme Obliquity Table)
5	48 degrees
6	46 degrees
7	44 degrees
8	42 degrees
9	40 degrees
10	38 degrees
11	36 degrees
12	34 degrees
13	32 degrees
14	30 degrees
15	28 degrees
16	26 degrees
17	24 degrees
18	22 degrees
19	20 degrees
20	18 degrees
21	16 degrees
22	14 degrees
23	12 degrees
24	10 degrees
25 or higher	Minimal (3d6-8 degrees, minimum 0)

Feel free to adjust a result from this procedure to any value between the next lower and next higher rows on the table.

If the result is Extreme, the obliquity is likely to be anywhere from about 50 degrees up to almost 90 degrees. To select a value at random, roll 1d6 on the Extreme Obliquity Table.

Extreme Obliquity Table
Roll (1d6)	Obliquity
1-2	50 degrees
3	60 degrees
4	70 degrees
5	80 degrees
6	98-3d6 degrees, maximum 90

Again, feel free to adjust a result from this procedure to any value between the next lower and next higher rows on the table.

Third Case: Planets Without Major Satellites

A Leftover Oligarch, Terrestrial Planet, or Failed Core which has no major satellite will be most affected by its primary star.

However, without the stabilizing presence of a major satellite, the planet’s obliquity is likely to change more drastically over time. Minor perturbations from other planets in the system may lead to chaotic “excursions” of a planet’s rotation axis. For example, although at present the obliquity of Mars is about 25 degrees (comparable to that of Earth), some models predict that Mars undergoes major excursions from about 0 degrees to as high as 60 degrees over millions of years.

To select a value for obliquity at random, begin by rolling 3d6 on the Unstable Obliquity Table.

Unstable Obliquity Table
Roll (3d6)	Modifier
7 or less	Roll 1d6 – High Instability
8-13	No modifier
14 or higher	Roll 5d6 – High Instability

Make a note of any result indicating High Instability for later steps in the design sequence. The planet is likely to be undergoing drastic climate changes on a timescale of millions of years.

Now make a roll on the Obliquity Table, but if High Instability was indicated, roll 1d6 or 5d6 on this table, rather than the usual 3d6. Finally, add the same modifier that was computed during Step Sixteen for the Rotation Period Table, based on the degree of tidal deceleration applied by the primary star. Refer to the Obliquity Table, and possibly the Extreme Obliquity Table, as required.

Examples

Both Arcadia IV and Arcadia V are planets without major satellites, so they both fall under the third case in this section, as they did in Step Sixteen.

For Arcadia IV, Alice begins by rolling a 4 on the Unstable Obliquity Table, indicating that she will need to roll 1d6 rather than 3d6 on the Obliquity Table. That roll will therefore be 1d6+1, and Alice gets a final result of 3. Arcadia IV apparently has extreme obliquity in the current era. Rather than roll at random, Alice selects a value for the planet’s obliquity of about 58 degrees.

Alice makes a note of the “high instability” of the planet’s obliquity. Its steep axial tilt may be a relatively recent occurrence, taking place over the last few million years. Arcadia IV, the Earth-like candidate in her planetary system, will have very pronounced seasonal variations, and may be undergoing an era of severe climate change. Any native life has probably been significantly affected, and human colonists would need to adapt!

Meanwhile, for Arcadia V, Alice rolls a 12 on the Unstable Obliquity Table, indicating that the planet’s rotational axis is currently relatively stable. She rolls an unmodified 3d6 on the Obliquity Table, getting a result of 15. She selects a value for this planet’s obliquity of about 28.5 degrees.

Architect of Worlds – Step Sixteen: Determine Rotation Period

September 9, 2020 Sharrukin Comments 0 Comment

A quick note before I drop the next section of the draft: I caught myself making several errors in the mathematics while developing this step. I think I’ve weeded all of those out, but if anyone is experimenting with this material as it appears, let me know if you come across any odd results.

Step Sixteen: Determine Rotation Period

The next three steps in the sequence all have to do with planetary rotation. Every object in the cosmos appears to rotate around at least one axis, and in fact some objects appear to “tumble” by rotating around more than one.

Planets and their major satellites usually have simple rotation, spinning in the same direction as their orbital motion, around a single axis that is more or less perpendicular to the plane of their orbital motion. There are, of course, a variety of exceptions to this general rule.

In this step, we will determine the rotation period of a given world. In this case, we will be dealing with what’s called the sidereal period of rotation – the time it takes for a world to rotate once with respect to the distant stars.

Worlds appear to form with wildly varying rotation periods, the legacy of the chaotic processes of planetary formation. However, many worlds will have been affected by tidal deceleration applied by the gravitational influence of nearby objects. Tidal deceleration may cause a world to be captured into a special status called a spin-orbital resonance, in which the world’s orbital period and its rotational period form a small-integer ratio.

Procedure

Begin by noting the situation the world being developed is in: is it a major satellite of a planet, a planet with its own major satellite, or a planet affected primarily by its primary star?

First Case: Major Satellites of Planets

Major satellites of planets, as placed in Step Fourteen, will almost invariably be in a spin-orbit resonance state. Most models of the formation of such satellites suggest that they are captured into such a state almost immediately after their formation.

Since a major satellite’s orbit normally has very small eccentricity, the spin-orbit resonance will be 1:1. The satellite’s rotation period will be exactly equal to its orbital period.

Second Case: Planets with Major Satellites

A Leftover Oligarch, Terrestrial Planet, or Failed Core which has a major satellite may be captured into a spin resonance with the satellite’s orbit. This is actually somewhat unlikely; for example, Earth is not likely to become tide-locked to its own moon within the lifetime of the sun. However, a satellite’s tidal effects on the primary planet will tend to slow its rotation rate.

To estimate the probability that a planet has become tide-locked to its satellite, and to estimate its rotation rate if this is not the case, begin by evaluating the following:

$T={10}^{25}\times\frac{M_S^2\times R^3}{A\times M_P\times D^6}$

Here, A is the age of the star system in billions of years. M_S and M_P are the mass of the satellite and the planet, respectively, in Earth-masses. R is the radius of the satellite, and D is the radius of the satellite’s orbit, both in kilometers.

If T is equal to or greater than 2, the planet is almost certainly tide-locked to its satellite. Its rotation period will be exactly equal to the orbital period of the satellite.

Otherwise, to generate a rotation period for the planet at random, multiply T by 12, round the result to the nearest integer, add the result to a roll of 3d6, and refer to the Rotation Period Table.

Rotation Period Table
Modified Roll (3d6)	Rotation Rate
3	4 hours
4	5 hours
5	6 hours
6	8 hours
7	10 hours
8	12 hours
9	16 hours
10	20 hours
11	24 hours
12	32 hours
13	40 hours
14	48 hours
15	64 hours
16	80 hours
17	96 hours
18	128 hours
19	160 hours
20	192 hours
21	256 hours
22	320 hours
23	384 hours
24 or higher	Resonance Established

Feel free to adjust a result from this procedure to any value between the next lower and next higher rows on the table.

The planet will be tide-locked to its satellite on a result of 24 or higher, or in any case where the randomly generated rotation rate is actually longer than the satellite’s orbital period. In these cases, again, its rotation period will be exactly equal to the orbital period of the satellite.

Third Case: Planets Without Major Satellites

A Leftover Oligarch, Terrestrial Planet, or Failed Core which has no major satellite may be captured into a spin-orbit resonance with respect to its primary star. Even if this does not occur, solar tides will tend to slow the planet’s rotation rate.

To estimate the probability that such a planet has been captured into a spin-orbit resonance, and to estimate its rotation rate if this is not the case, begin by evaluating the following:

$T={(9.6\ \times10}^{-14})\times\frac{M_S^2\times R^3}{{A\times M}_P\times D^6}$

Here, A is the age of the star system in billions of years, M_S is the mass of the primary star in solar masses, M_P is the mass of the planet in Earth-masses, R is the radius of the planet in kilometers, and D is the planet’s orbital radius in AU.

Again, if T is equal to or greater than 2, the planet has almost certainly been captured in a spin-orbit resonance. Otherwise, to generate a rotation period for the planet at random, multiply T by 12, round the result to the nearest integer, add the result to a roll of 3d6, and refer to the Rotation Period Table. The planet will be in a spin-orbit resonance on a result of 24 or higher, or in any case where the randomly generated rotation rate is actually longer than the planet’s orbital period.

Planets captured into a spin-orbit resonance are not necessarily tide-locked to their primary star (or, in other words, the resonance is not necessarily 1:1). Tidal locking tends to match a planet’s rotation rate to its rate of revolution during its periastron passage. If the planet’s orbit is eccentric, this match may be approximated more closely by a different resonance. To determine the most likely resonance, refer to the Planetary Spin-Orbit Resonance Table:

Planetary Spin-Orbit Resonance Table
Planetary Orbit Eccentricity	Most Probable Resonance	Rotation Period
Less than 0.12	1:1	Equal to orbital period
Between 0.12 and 0.25	3:2	Exactly 2/3 of orbital period
Between 0.25 and 0.35	2:1	Exactly 1/2 of orbital period
Between 0.35 and 0.45	5:2	Exactly 2/5 of orbital period
Greater than 0.45	3:1	Exactly 1/3 of orbital period

On this table, the “most probable resonance” is the status that the planet is most likely to be captured into over a long period of time. It’s possible for a planet to be captured into a higher resonance (that is, a resonance from a lower line on the table) but this situation is unlikely to be stable over billions of years.

Examples

Both Arcadia IV and Arcadia V are planets without major satellites, so they both fall under the third case in this section. The most significant force modifying their rotation period will be tidal deceleration caused by the primary star.

The age of the Arcadia star system is about 5.6 billion years. Arcadia IV has mass of 1.08 Earth-masses and a radius of 6450 kilometers. Alice computes T for the planet and ends up with a value of about 0.083. Arcadia IV is probably not in a spin-orbit resonance, but tidal deceleration has had a noticeable effect on the planet’s rotation. Alice rolls 3d6+1 for a result of 11 and selects a value slightly lower than the one from that line of the Rotation Period Table. She decides that Arcadia IV rotates in about 22.5 hours.

Meanwhile, Arcadia V has mass of 0.65 Earth-masses and a radius of 5670 kilometers. Alice computes T again and finds a value of about 0.007. (Notice that the amount of tidal deceleration is very strongly dependent on the distance from the primary.) Alice rolls an unmodified 3d6 for a value of 12, this time selecting a value slightly higher than the one from the table. She decides that Arcadia V rotates in about 34.0 hours.

Citations

Gladman, Brett et al. (1996). “Synchronous Locking of Tidally Evolving Satellites.” Icarus, volume 122, pp. 166–192.

Makarov, Valeri V. (2011). “Conditions of Passage and Entrapment of Terrestrial Planets in Spin-orbit Resonances.” The Astrophysical Journal, volume 752 (1), article no. 73.

Peale, S. J. (1977). “Rotation Histories of the Natural Satellites.” Published in Planetary Satellites (J. A. Burns, ed.), pp. 87–112, University of Arizona Press.

Architect of Worlds – Step Fifteen: Determine Orbital Period

September 8, 2020 Sharrukin Comments 0 Comment

So, for the first time in over two years, here is some new draft material from the Architect of Worlds project. First, some of the introductory text from the new section of the draft, then the first step in the next piece of the world design sequence.

The plan, for now, is to post these draft sections here, and post links to these blog entries from my Patreon page. None of this material will be presented as a charged update for my patrons yet. In fact, there may be no charged release in September, since this project is probably going to be the bulk of my creative work for the next few weeks. At most, I may post a new piece of short fiction as a free update sometime this month.

Designing Planetary Surface Conditions

Now that a planetary system has been laid out – the number of planets, their arrangement, their overall type, their number and arrangement of moons, all the items covered in Steps Nine through Fourteen – it’s possible to design the surface conditions for at least some of those many worlds.

In this section, we will determine the surface conditions for small “terrestroid” worlds. In the terms we’ve been using so far, this can be a Leftover Oligarch, a Terrestrial Planet, a Failed Core, or one of the major satellites of any of these. A world is a place where characters in a story might live, or at least a place where they can land, get out of their spacecraft, and explore.

Some of the surface conditions that we can determine in this section include:

Orbital period and rotational period, and the lengths of the local day, month, and year.
Presence and strength of the local magnetic field.
Presence, density, surface pressure, and composition of an atmosphere.
Distribution of solid and liquid surface, and the composition of any oceans.
Average surface temperature, with estimated daily and seasonal variations.
Presence and complexity of native life.

In this section, we will no longer discuss how to “cook the books” to prepare for the appearance of an Earthlike world. If you’ve been following those recommendations in the earlier sections, at least one world in your designed star system should have a chance to resemble Earth. However, we will continue to work through the extended example for Arcadia, focusing on the fourth and fifth planets in that star system.

Step Fifteen: Determine Orbital Period

The orbital period of any object is strictly determined by the total mass of the system and the radius of the object’s orbit. This is one of the earliest results in modern astronomy, dating back to Kepler’s third law of planetary motion (1619).

Procedure

For both major satellites and planets, the orbital period can be determined by evaluating a simple equation.

First Case: Satellites of Planets

To determine the orbital period of a planet’s satellite, evaluate the following:

$T\ =(2.77\ \times{10}^{-6})\ \times\sqrt{\frac{D^3}{M_P+M_S}}$

Here, T is the orbital period in hours, D is the radius of the satellite’s orbit in kilometers, and M_P and M_S are the masses of the planet and the satellite, in Earth-masses. If the satellite is a moonlet, assume its mass is negligible compared to its planet and use a value of zero for M_S.

Second Case: Planets

To determine the orbital period of a planet, evaluate the following:

$T\ =8770\ \times\sqrt{\frac{D^3}{M}}$

Here, T is the orbital period in hours, D is the radius of the planet’s orbit in AU, and M is the mass of the primary star in solar masses. Planets usually have negligible mass compared to their primary stars, at least at the degree of precision offered by this equation, and so don’t need to be included in the calculation.

Examples

The primary star in the Arcadia system has a mass of 0.82 solar masses, and the fourth and fifth planet orbit at 0.57 AU and 0.88 AU, respectively. The two planets’ orbital periods are about 4170 hours and 7990 hours. Converting to Earth-years by dividing by 8770, the two planets have orbital periods of 0.475 years and 0.911 years.

Alice has decided to generate more details for the one satellite of Arcadia V. This is a moonlet and so can be assumed to have negligible mass, while the planet itself has a mass of 0.65 Earth-masses. The moonlet’s orbital radius is about five times that of the planet, and Alice sets a value for this radius of 28400 kilometers. The moonlet’s orbital period is about 16.4 hours.

Architect of Worlds: The Next Chunk

August 24, 2020 Sharrukin Comments 1 comment

While I’m waiting for my consulting editor to have a look at The Curse of Steel, I’ve turned back to a project that I’ve been neglecting for too long: the world-building book Architect of Worlds. Several sections of that book already exist in a rough draft, which can be found at the Architect of Worlds link in the sidebar.

The bulk of the material I’ve already written is a design sequence, permitting the user to set up fictional star systems (or to fill in details for real-world systems). The idea is to let SF writers, game designers, tabletop game referees, and so on design locations for interstellar SF settings, using whatever combination of random chance and deliberate choice they prefer. The emphasis is on “hard SF” realism, as far as the state of exoplanetary astronomy will permit, and no dependencies on any specific tabletop rules system.

So far, the draft system permits one to place stars, planets, and moons, and get gross physical properties (mass, density, surface gravity) and dynamic parameters (orbital radius, eccentricity, and period) for each.

The next slice of the system will involve generating the surface conditions for such bodies, at least for the small “terrestroid” worlds that are likely to provide environments for SF adventure. At this point we’re talking about things like surface temperature (average and variations), atmospheric composition and pressure, the amount and state of water (or other volatiles) on the surface, what kind of native life might be prevalent, and so on.

I’ve been mulling this section over for a few years now, since the science involved is a lot more complicated and more difficult to reduce to a set of game-able abstractions.

When I designed a system like this for GURPS Space Fourth Edition, I made a deliberate design choice to reduce all the possibilities to a specific set of archetypes. That provided some backward compatibility with earlier versions of the GURPS system, and with the older Traveller systems that were an inspiration for both. For this book, though, I want to give the readers as much detail as I can, and let them decide what to use and what to set aside. That complicates the design.

So, a very rough overall outline of what’s going to be involved for a given “world” (that is, a terrestrial planet or moon with some likelihood of a solid surface):

The rotation rate of the world (including cases where the world is tide-locked or resonant with a primary). As a sidebar, this gives us quantities for the length of the natural day, month, and year.
The blackbody temperature and incidence of stellar wind for the world, based on the properties and distance of its primary star.
The strength of the world’s magnetic field, and the consequences for the size and strength of its magnetosphere (if any). If the world is a moon (for example, the satellite of a gas giant planet), then the primary’s magnetic field and magnetosphere may be relevant as well.
The world’s initial budget of volatiles – how much in the way of possible liquid or gaseous compounds was the world left with after its process of formation.
Atmospheric composition – what volatile compounds are likely to be gaseous at local temperatures, and can the planet hold onto them?
Atmospheric mass and pressure.
Hydrospheric composition – what volatile compounds are likely to be liquid or solid instead?
Hydrospheric mass and prevalence – how much of the world’s surface will be covered by what kinds of liquid or solid stuff?
Average surface temperature.
Estimated variations in surface temperature with the position on the surface, time of day, and so on.
Presence and complexity of native life – which may require a loop-back to adjust characteristics of the atmosphere, hydrosphere, and surface temperature.

All that’s the minimum for what the next section of the book needs to cover. There are a lot of dependencies back and forth here, which is one reason why I’ve struggled for so long to build this piece. I’m beginning to think I see how to design something workable, though. At least enough to get started. More over the next few weeks.

The Great Lands: Revatheni Local Map

June 3, 2020 Sharrukin Comments 0 Comment

. . . and here we have the last of the maps I needed to build before getting started on revisions of The Curse of Steel. Over the past couple of months, I’ve gone from maps covering two whole continents (and their history) to a map covering a major region, and now down to this local map. The entire action of the novel will take place within the territory covered by this map.

This map focuses on the lands held by the Revatheni clan confederation of the Tremara people. The Revatheni (the name means something like “those who dwell by the sacred grove”) occupy most of the land between the Dugava and Kanta Rivers, a territory totaling about 11,500 square miles. The total population of the clan confederation is about 140,000, divided among five major clans and a dozen or so minor ones. The Revatheni are an unusually wealthy tribe, partaking in a lot of the trade coming up the rivers from the south. For the past couple of generations, their leaders have been putting on airs, claiming increased privileges and calling themselves sarai (“kings”).

As with the regional map, this is a fairly finished project – I’ve placed and named all the settlements and terrain features that are likely to play any part in the revised novel. The next step is to get busy with the second draft! I hope to have the novel ready for release sometime this fall.

The Great Lands: Tremara Regional Map

May 31, 2020 Sharrukin Comments 0 Comment

Having finished the “historical atlas” series for the Great Lands, now I’m starting to focus on maps that will help me keep track of the environment in which my characters will be moving around. This is a map of the territory inhabited by Krava’s home culture and the surrounding region.

The Tremara inhabit the region between the Blue Mountains in the west, the Black River valley in the east, the great pine forests of the Northmen, and the Lake Country to the south. It’s an area of roughly 200,000 square miles, supporting a total population of about 2.4 million. The Tremara are at an early Iron Age level of development – mostly peasant villages, ruled by a warrior aristocracy who fight from chariots with bow and spear. They have some contact with Korsanari and Sea Kingdom merchants who bring in luxury goods and new ideas – these mostly come up the rivers from the Lake Country, or across the Blue Mountains at the Trader’s Pass.

This map is a reasonably finished project, although I expect I’ll continue to tweak and add to it in the future as I develop more details of the setting.

Next project will be to focus on a small area of this map, producing a local map that should cover all the territory that plays a part in The Curse of Steel. Once that’s done, I’m probably going to have everything I need to sit down and produce a second draft of the novel.

Technical Notes: My continent-wide map was put in an orthographic projection and narrowed down to this region using GProjector (Windows version 2.1.8). An image from there was imported as a tracing overlay, and the basic map here was produced, using Wonderdraft (version 1.1) with standard symbol libraries. The final Wonderdraft product was imported into Adobe Photoshop CC, where I added the latitude-longitude grid and all the place names. I have another overlay (not visible here) with national and tribal names.

Last Call for the Historical Atlas

May 25, 2020 Sharrukin Comments 0 Comment

I’m making very good progress in compiling the Historical Atlas of the Great Lands.

This document is going to describe some of the basic assumptions of the Great Lands setting, laying out its large-scale history with a series of maps and a timeline. The final draft looks like it’s going to be about forty pages and 12,500 words, with fifteen maps. The finished product will be part of my setting bible, and will probably become an integral part of any RPG sourcebook I publish for the Great Lands in the future.

If you’ve been following my posts here for the past six weeks, you’ve seen at least early drafts of most of this material – but the final version has another coat of polish, and some new content as well.

Best guess is that I’ll be releasing the Historical Atlas sometime on Tuesday, 26 May 2020. It will be available to all of my patrons, from the $1 level up. If you want a copy and you haven’t signed up yet, now’s a good time to head on over to my Patreon page.

The Great Lands: Historical Atlas (Present Day)

May 22, 2020 Sharrukin Comments 0 Comment

As the Iron Age matures throughout the Great Lands, societies everywhere have begun to transform themselves. This will not be an era of tiny tribal states, leavened with the occasional “Great Kingdom” that is still small in territorial extent. New military technologies and social organizations are clearly giving rise to an age of empire.

The superpower of the day is the Anshan Empire, the largest and most populous single state in world history up to this point. The Anshani have conquered the entire core of the Kurani zone, along with most of the old Nesali heartland and all of the upper Mereti lands. By Krava’s time they are pressing down on the Korsanari city-states of the coast, and are in a constant state of low-level war with the resurgent Mereti Kingdom in the far east. No one is quite sure what further ambitions the Anshani hold, but their kings and their jealous god show no sign of slowing down.

With the Tukhari homeland under Anshani rule, many of the colonies in the east have banded together for mutual support and defense. The core of the alliance is the city of Tukhar Nakh (“New Tukhar”), which has grown to significant size on the basis of its prosperous trade links. The allies are nominally independent of Anshani rule, and would fight Anshan if the Empire ever forced them to it. In the meantime, their interests align with Anshan more often than not, especially when it comes to holding the other great sea-faring powers at bay.

The Sea Kingdom remains relatively peaceful in strategy and intent . . . although in recent generations it has developed a truly formidable capacity for self-defense against the various “barbarians” it finds across the world. Sea Kingdom ships go wherever they choose and trade with whoever is willing, and not even Anshan has quite mustered the courage to try to oppose them. As a result, the lords of Dar-ul-Hakum have become fabulously wealthy, trading in all the luxury goods of the world. With wealth comes great power, which the Sea Kingdom has not yet decided how to use . . .

One unique facet of the Sea Kingdom’s holdings is the appearance of the Island-folk, finally reunited with all their distant cousins after tens of thousands of years. The Island-folk embraced the arrival of the Sea-Kingdom’s first ships in their distant homeland, and enthusiastically volunteered to serve aboard Sea-Kingdom ships. Over the last few generations, they have set up small communities in almost every port town in the world. Their clever minds and nimble hands make them valuable in a variety of professions: sailors, craftsmen, messengers and thieves.

The third of the great sea-faring powers is the Korsanari city-states. Like a shadow of the ancient Kavrian Matriarchy, the Korsanari have begun to build a sophisticated urban civilization of their own. The Korsanari are not venturesome sailors like the Tukhari or the Sea-Kingdom, rarely willing to sail out of sight of land. Even so, they have set up their own trade networks throughout the Sailor’s Sea and beyond. These networks are supported by a plethora of small colonies, established wherever a decent harbor and a sheltered hinterland can be found, and the local barbarians are not too hostile.

The Korsanari have also begun to trade well inland on the northern continent, seeking markets where the Tukhari and even the Sea Kingdom do not bother to go. Korsanari merchants have penetrated as far as the Lake Country and beyond, bringing the Tremara and even some of the skatoi tribes into their trade network.

As for the Tremara, Krava’s people? They are thoroughly established between the Blue Mountains and the skatoi lands across the Black River, with the pale Mervirai tribes to the north and the prosperous Lake Country to the south. Compared to the vibrant cultures around the Sailor’s Sea, they are certainly barbarians – but sophisticated barbarians, with superb visual art, even better poetry and music, and the beginnings of a literary tradition. Most of the peoples of the Great Lands know little about them and care less, but (in the persons of Krava the Swift and her friends) they are about to shake the world . . .

The Great Lands: Historical Atlas (300 BP)

May 20, 2020 Sharrukin Comments 0 Comment

Late in the Bronze Age, iron-working technology appeared in two wide-separated places. The growing Sea-Kingdom was the first to mass-produce iron for tools and weapons, guided by the occasional instruction of the Elder Folk. The late Nesali Empire developed the new technology as well, with input from the Smith-folk enclave in their territory. The chaos of the Bronze Age collapse spread the new technique far and wide.

By the time the völkerwanderung faded, the world had changed. Almost all of the Great Kingdoms at the core of the civilized region had collapsed. The Mereti Kingdom had fallen down to a small rump state, due not to foreign invasion, but to internal decadence and anarchy. The Empire of Shuppar was gone, only its capital city remaining behind to testify to faded glory. The Nesali Empire had vanished entirely from history, leaving behind a patchwork of petty kingdoms and tribal states.

Yet new powers were also on the rise.

The Kingdom of Anshan applied iron weaponry and innovative tactical systems to place most of Shuppar’s old territory under heavy tribute. The Anshani people were soon cordially hated by all of their subjects and neighbors . . . but their armies and ruthless administration made them the new imperial power.

Meanwhile, mercantile power was making its appearance for the first time. To be sure, the high Bronze Age had boasted extensive trade networks, but these mostly involved traffic among kings and aristocrats in luxury goods. Now the Kurani city-states of the coast, most notably the towns of Buradh and Tukhar, began to trade far out across the Sailor’s Sea. The Tukhari, in particular, established trading posts and small colonies along both shores of the sea, reaching as far as the open Sunset Ocean. In part, this movement was driven by Anshani pressure; the coastal towns needed to raise great wealth to hold off imperial armies. Yet it was noteworthy that these trading ventures were led and manned by commoners, men and women of no noble blood.

And as the Tukhari venturers reached the Sunset Ocean, they encountered the men of the Sea Kingdom coming the other way.

After a thousand years of isolated development, the Sea Kingdom was ready to explore the whole world. Huge ocean-worthy ships returned to the Great Lands, establishing trading posts all up and down the western coasts, some of them venturing as far as the Mereti coast in the far east. From these outposts, wild tales came of strange lands no other man had ever seen, on the far side of the Sunset Ocean and even on the other side of the world.

The Sea Kingdom was peaceful to a fault in this era, refusing to use force to compete for trade or territory. But then, their arts and sciences were far enough beyond those of the Great Lands that they had no need to use force. No one, not even the most ruthless Anshani prince or Tukhari merchant, dared lift a hand against them. And where the sailors of the Sea Kingdom went, iron-working and the arts of civilization followed. Even the Muri cultures of the deep south came into the world community at last, picking up advanced technology and social systems from visiting Sea Kingdom ships. Several Muri tribal confederations became full kingdoms in this era, and a Muri dynasty established itself in the new Ka realm that had arisen as a rival to the Mereti.

In the north, the skatoi had settled down in what was once Rudanai territory, splitting the Maras cultures almost in half. They proved poor neighbors, although the Maras soon found that they spent as much time fighting one another as raiding outsiders.

The eastern Maras peoples established a stable status quo. The Haleari even built a network of city-states, reminiscent of the Tamiri civilization that had fallen in the same area a thousand years before. In the west, the Chariot People continued to expand, taking over the remaining Zari lands east of the Blue Mountains. One branch of the northern Kardanai were destined for special significance. These were the Tremara (Classical Korsanai trenāras, the “Mighty Folk”) – Krava’s own people, out on the historical stage at last.

The Great Lands: Historical Atlas (700 BP)

May 18, 2020 Sharrukin Comments 0 Comment

Just as in our own world, the end of the Bronze Age came amid chaos.

The first act took place in the west, where the Targut Horde of the skatoi sought to move south into warmer and more fertile lands. At first they tried to invade the fringes of Zari territory, near the Standing Stones. An alliance of Zari villagers, Maras charioteers from the south, and the Elder Folk turned back this invasion at the famous Battle of the Plain. This turned the Targut aside, forcing them to stick to the eastern side of the Black River.

About a generation later, a civil war among the far-northern Akyat Horde caused about two-thirds of that people to move southward, pushing aside the Marut Horde. The Marut responded by allying themselves with the Targut, mounting a great war-migration into the Maras lands north and east of the Great Lakes. The Rudanai tribes who dwelt there soon found that they no longer had a military advantage over the skatoi, who had tamed horses and built war-chariots of their own.

While this was going on, the Korsanari of the south fell into a trap of their own. Using divine blessings and the power of a mighty Smith-folk-forged sword, one of the palace-lords unified most of the Korsanari for the first time in history. Unfortunately, his arrogance led to a war against the very Smith-folk who had aided him in his youth. This led to his downfall under a curse, and the collapse of his High Kingdom. After his death, his vassals turned against one another, fighting over the scraps until there was little left. His sword vanished from history, only to fall into the hands of Krava the Swift centuries later.

Like the fall of a cascade of dominoes, the migrations continued southward. Attracted by the chaos in Korsanari lands, the Rudanai moved southward, sacking palace after palace as they went. Some of them surged out across the narrows of the sea, capturing islands and carving big chunks out of the Nesali Empire. After a generation of this, the Nesali themselves collapsed, setting off a further wave of migration that rushed into Kurani lands.

The Second Empire of Shuppar had managed to hang on until this point, although much of its old territory had already fallen away by the time the wave of Rudanai and Nesali migrants arrived. Now the empire collapsed entirely, although the city of Shuppar itself survived the wave of destruction. The only beneficiary of this chaos was the kingdom of Anshan, which broke violently away from Shuppar early in the chaos, and managed to hold the Maras migrations at bay. Driven by their blood-thirsty god and a massive sense of racial superiority, the Anshani suddenly saw their own chance for empire . . .