Traveller My 3I

My 3rd Imperium: History


Official 3rd Imperium History

The Traveller 3rd Imperium setting has an official history with the players starting in year 1105.

which says the 3I has been running the Spinward Marches for c. 700 years. This is too long for the feel I want.

My Alternate Timeline

In my Traveller universe I’m saying it took the 3I longer to expand, roughly an average of 50 years per sub-sector in any direction so as Vincennes in Deneb is c. 16 sub-sectors away from the core say it took c. 800 years to get to the edge of the Spinward Marches.

800: edge of Spinward Marches

850: Mora

900: Trin’s Veil, Rhylanor and Lunion

950: Glisten, Lanth, parts of Regina and Aramis – Jewell seeks 3I protectorate.

1000: Vilis, Regina – Jewell associate

1050: Five Sisters

In progress: building up Aramis, Vilis, Five Sisters, improving route to Five Sisters, Jewell, diplomacy District 268

So Mora has been part of the 3I for c. 250 years, Glisten c. 150, Vilis c. 100 years, Five Sisters c. 50 years – much more frontiery.

Population Sizes

The systems in Spinward could have been colonized by

  • the Ancients: humans, modified humans or others
  • the Vilani
  • Second Imperium
  • Third Imperium

so large populations aren’t surprising. The Marches are the 3I’s frontier but they are not frontier in the sense of being undeveloped.

Also in between the big empires, alpha systems may have risen and fallen creating their own pocket empires for a time so there cab be ruins everywhere.

Frontier Wars

In the official history there have been a number of Frontier wars with the Zhodani mostly revolving around Jewell

  • two in the 600s
  • one in the 900s
  • two more in 1080 and 1107

In my alternative time line the first three are bumped up and the second two stay the same

  • the first three involved escalating skirmishes in the 950s with the Jewell cluster’s own fleet itself being the largest force
  • well planned major Zhodani attack 1080
  • 5th Frontier war incoming

Player Start

any of

1065: second survey

1082-1084: 4th Frontier War

1085 to 1104: a bit less impending war (but potential for salvage, lost ships, spy stuff etc)

1105: standard start, big war incoming

or even way back 800-900 when the Imperium’s border was still in Deneb.



Warning – this whole post is a spoiler.

Official Version

In the 3rd Imperium setting of Traveller there are a species called the Ancients who did stuff and a boss dude called “Grandfather” more or less detailed here:


Anyway in my quest to include every existing sci fi trope in the Spinward Marches…


My Version

Grandfather and the actual Ancients are D&D mind flayers / Cthulhu Starspawn type creatures – the Droyne are a servitor species.

They developed immortality requiring some kind of vampiric process.

Not nice.

They were big on genetic engineering and mass gladiator battles.

They picked up humans and modified them, sometimes just for fun, sometimes for practical reasons so they could work more easily on a particular world with droyne as slave drivers but they also used them for war-sized gladiator type battles e.g. Waterloo or Kursk sized, including Mecha type battles and battles against giant robots – Vland still has a cultural memory of these. The gladiator humans were generally left unmodified to make the battles even.

The Ancients liked to bet on the outcomes of the battles.

Sometimes Ancients would control the battles directly using psionic powers to give orders to the officers on the ground like a computer game with real blood.

Anyway apart from all that the Ancients built all kinds of high tech wonders – artificial planets, ring worlds etc blah blah.

They also built a robotic fleet with an AI which – you guessed it – went rogue and developed a version of the Prime Directive: that it was wrong for a space-faring species to interfere with a non space faring species. After the Ancients refused to obey the Fleet’s order to desist (and as despite all their psionic powers they couldn’t regain control of their robotic forces) the Fleet attacked and destroyed all the Ancient’s industrial worlds, anything capable of building ships and anything that could become capable of building ships.

Only Grandfather and 420 Ancients survived this destruction most of them on research stations on worlds with little other infrastructure.

Fleet moved out into the universe looking for other breakers of its Prime Directive but not before leaving behind TL18 stealth ships containing hunter killer terminator robots to hunt down the last remaining Ancients.

Grandfather escaped into a pocket universe while the others were hunted down – not all were however, many of them found a way to hide. The terminators, stealth ships and Ancients are still there in the OTU hidden.

Consequences in Game

– hidden TL18 stealth ships in system with unaccounted for Ancients, literally hidden just sitting on a moon somewhere powered down for thousands of years waiting for a scent

– Terminators, some on the stealth ships, some on planets. The ones that got their target designed to self-destruct but those who never found their target just power down and wake up every few centuries to sniff. Invisible in stealth armor one could be sitting on the roof of an Ancients site powered down while Imperial archaeologists work below.

Terminator – botched self-destruct, mangled Terminator somewhere

– Surviving Ancients who hid themselves in various ways to evade the Terminators: cybernetic Dalek form, bio-engineered form, stasis, sealed inside an impregnable tomb etc

– Grandfather, if players find his pocket universe he tells them various lies to get them to check out systems where there may be a surviving Ancients and/or tries to get them to find and destroy Terminators for him. Say c.120 of the surviving 420 Ancients were killed by Terminators and he’s rescued c. 100 over the years and he’s still trying to gather in the remaining 200 or so.

– wandering Ancients – possibly transformed to hide scent from terminators

– misfiring Terminators – an Ancient created an item to act as a decoy which gives off Ancient’s scent, players find it


 Vlandian Games

As mentioned Vland retained a cultural memory of their role in the Ancients gladiatorial games particularly the Vilani gladiators having to fight giant robots. This passed down through festivals and semi-religious symbolism but after the development of grav tech spawned an entertainment involving giant Mechs with teams of players inside controlling them. This is now an interstellar sport with a league in many sub-sectors.


Trade Network


My Spinward Marches Trade Map


(courtesy of the awesome )

  • dark green routes are the hinterland routes
  • purple are the long distance routes between alpha systems – these also overlay some of the hinterland routes
  • light green routes are subsidized by the Imperium for policy reasons (e.g. building up border systems)
  • yellow circles are alpha systems (and sub-sector capitals if different)


Trade Assumptions

1) Systems represent whole solar systems so from TL9+ onwards worlds can easily be self-sufficient in raw materials.

2) Interstellar shipping costs per ton per parsec are high so

  • it’s only going to be economic to ship low value goods a short distance, say one or two parsecs, and only to systems which might have demand in excess of what the system can produce itself
  • medium value goods are restricted in a similar way, say up to six parsecs
  • high value goods: tech, luxury items, rare materials, unique planetary items etc can be profitably transported long distances but only in large amounts to systems which have a high demand for high value goods i.e. rich, high population planets



Trade in Traveller will mostly revolve around the alpha planets.

(Defined IMTU as class A star port, pop 8+, TL 12+.)

1) The alpha systems have high value tech to trade for what they want.

2) The alpha systems might have a demand for common raw materials because they have already used up the easiest sources in their system so deep mined local copper might be more expensive than copper that is open mined on a nearby system and then shipped – as long as it is nearby.

3) Assuming that an alpha planet can always grow enough food to feed their billions even if it’s in vats or on orbital stations or whatever they might still consider “natural” food items as a luxury or preference especially things like meat and fruit so I can see alpha systems having a demand for those from nearby systems – again stressing nearby.

4) The alpha planets will provide the main market for high value goods simply because their population size and TL implies they will have a large market and lots of prosperous or wealthy individuals.

So the alpha planets are the main markets and provide the hubs of trade.



If you accept the conclusion then the nature of trade in the Imperium will resolve into three main categories:

1) Hinterland Trade

Each Alpha system will have a cluster of systems around them which are tied to that Alpha’s economy. The hinterland systems will generally provide something useful for tech.

  • very short distance, 1-2 parsecs, for low value goods
  • short distance, up to 6 parsecs for medium value goods

The clusters made up of an alpha and its hinterland would once have been the core of the many pocket empires swallowed up by the Imperium as it expanded.

2) Silk Road Trade

Long distance trade between the alphas. Ships plying these routes don’t need to trade with the systems in between so these routes generally take the form of truck stops with an orbital refueling station by an outer gas giant or ice planet. The hub to hub ships just jump in, dock, refuel and do maintenance checks at the space station then jump out again. They only stop to unload when they reach the destination. Silk road truck stops will generally have a small 3I naval base for protection – like a Roman fort.

3) BackwaterTrade

Most everywhere else will have relatively low volumes of trade providing a living for Book 2 type subsidized merchants and Free Traders.



The alpha planets will often have orders of magnitude more people, GDP, tax etc than the rest of their sub-sector so not only will they both physically produce the fleets and provide the revenue to support them – so in terms of fleets – the bedrock of the Imperium – the alpha planets are what matters.

More specifically what matters in order
1) alpha planets
2) routes between the alpha planets
3) border fortress systems
4) alpha clusters
5) everywhere else

This leads to my 3I being split into three layers

  • there is a big ship universe of dreadnoughts and megacorporations comprising all the alpha systems and the silk road systems linking them
  • there is a medium ship universe in the hinterland systems of each alpha cluster
  • there is a small ship universe everywhere else where the 3I is rarely seen

(where small <= 1200-1600, medium <= 5k dtons, big > 5k dtons)


Which systems are which?

You could do it the GURPS way of giving systems a trade value based on their world stats but I think the potential self-sufficiency of systems and the consequent randomness of whether or not a system has something worth selling to an alpha makes a random element to trade value both plausible and potentially more interesting so IMTU I’m going to treat the canon star port class as the indicator of trade value i.e. if they built it there was a good reason so:

1) Alpha Systems: the alpha systems are defined as class A, pop 8+, TL 12+ (and sub-sector capitals)

2) Hinterland Systems: non-alpha systems with A or B star ports within 6 parsecs of an alpha system are assumed to have something to sell to the alpha in exchange for tech and are part of that alpha’s hinterland cluster

3) Exotic Systems: A or B systems outside of an alpha cluster (more than 6 parsecs) will generally have an exotic explanation. It could be something shady, historical or unusual like the system is being actively built up by the Imperium for some reason with regular colonist ships from the core

4) Backwater Systems: C, D and E systems are assumed to not have much anyone else needs and so have a low volume of trade serviced by Book 2 type ships

5) Silk Road Truck Stops: systems that make convenient refueling stops on the silk road.

6) Hinterland Truck Stops: systems that make convenient refueling stops on hinterland routes.


Example: Glisten sub-sector

1) Glisten is an alpha system.

2) Mertactor, Mille Falcs, Egypt, Overnale, New Rome, Aki, Weiss, Dobham are all hinterland systems and part of Glisten’s cluster

3) Romar, Bendor, Squanine, Ffudn are both hinterland systems and silk road truck stops

4) Mithras, as a prison planet is part of Glisten’s hinterland also

5) Grote is an exotic exception system – it could be a system being actively built up by the Imperium as a border fortress and link to District 268 or something odd / shady.

6) Aster, Melior, Craw, Horosho, Wurzburg, Lydia, Centry, Bicornn, Crout, Tirem, Caledonia are backwaters

7) Callia, Sorel, Tsarina, Windsor, Trane, Inthe are backwaters and hinterland truck stops

8) Marastan is a backwater and a silk road truck stop

  • systems like this are part BSU and part SSU and will generally have a commercial orbital station which services the passing merchant ships and small ships linking to the planet itself. Players jumping into the system might see lots of big silk road freighters and lots of patrolling fighters between the naval station and the jump points but very little traffic near the main planet.


Ship Encounters

Alpha Systems
  • very busy, lots of colonized planets and moons, lots of habitats, masses of internal traffic plus lots of large, medium and small interstellar traffic. Lots of planetary defenses – especially around fuel sources. Naval ships up to dreadnoughts. Silk road patrol ships.
Hinterland Systems
  • less busy, medium and small commercial ships, medium naval patrol ships.
Backwater Systems
  • quiet, small commercial ships, belters, scouts, small naval patrol ships.


Imperial Nobility

The Imperium is huge and travel is slow so the Capital may be a year or more away from the frontier.


Historically this sort of problem is solved by decentralization and the problem that arises from that – risk of rebellion – is solved with some kind of feudal structure – hence the importance of the nobility in Traveller.


There are a lot of different historical models for this so the question is which suits the Traveller OTU best.

Apparently the Traveller nobility were based on the Russian Imperial model of Boyars and that does seem to me to be a good model.

So I’ll use that as the basis for the nobility IMTU

The key distinction is that being a member of the Boyar class doesn’t automatically imply actual Imperial authority. Imperial authority comes from Imperial titles. Being a member of the Boyar class is pre-requisite for getting a title but the two are separate.


Becoming  Boyar

When someone reaches certain ranks in the Imperial service (particularly the Navy) they get either a lifetime or hereditary knighthood and become part of the Boyar class e.g. a Navy Captain gets an honorary knighthood and lifetime membership of the Boyars, an Admiral gets a hereditary knighthood.

A lifetime knight gets the title and some standard perks like the right to bear arms. A banner knight gets those and also a knight’s fee – ttile to some land and a hereditary source of income.

Knight’s Fee

Let’s say the Imperium taxes 25% of star port revenue traditionally divided

– 5% to Capital

– 5% to Sector

– 5% to Sub-Sector

– 10% as knight’s fees

Say traditionally a knight’s fee was 0.001% of a star port’s revenue so the 10% above would be 10,000 knight’s fees however this was A class star ports on the core worlds so the percentage may vary greatly. A knight’s fee from a C star port on a backwater planet might be 1% and ten knights. The fee from an even more backwater D star port might the full 10% and a single knight.

Once a Boyar then additional promotion to an Imperial title gains extra fees.

If a later member of a Boyar family also reaches such a rank they get additional knight’s fees.


The Imperium is governed through titles. For example the commander of a sub-sector’s scout service might have the title of Baron-Commander. The commander of a sector scout service has the title Count-Commander. The commander of a particular interdiction or imperial prison planet might be a knight-commander.

So knight and banner knight simply denote Boyar status. Knight-commander, Baron, Count, Duke etc denote Imperial titles and the titles confer imperial authority over their assigned facet of imperial governance.

Sample Career

A commoner joins the navy and rises to Captain and is knighted, switches to “Noble” career and spends a term as the Knight-Commander of a prison ship followed by a term as the Baron-Commander of a designated colony project, then a term as the Count-Commander of the sector scout service then a term as sub-sector Duke and then finally a term as sector Duke.

Each promotion would get a fee so five fees in this case.

If their great-grandson becomes an admiral later they would add another fee to the family collection.


Types of Noble

The distinction between Boyar and title means there are various types of noble.

1) Standard Banner Knight

The family gained a fee or two some time in the past but haven’t added more to it since. They have an estate and some funds but they are not wealthy. Most join the Imperial service in some form for some amount of time.

2) Wealthy Banner Knight

Often these are families that got fees on under developed planets that have since developed. A Boyar family who owned a lot of the land around a D star port on a low population world which eventually grew into a B star port on a developed world might own 10% of everything on the planet. The family would still only be Boyars and have no imperial authority but could be fabulously wealthy with a great deal of unofficial authority based on their wealth and local status. A family like that could actually run things behind the scenes with any government type.

3) Imperial Title

A Knight (from either of the two backgrounds above) who has an imperial title will have authority and power commensurate with their position: a Knight-Commander of an interdiction might have a squadron of ships, a Knight-Ambassador on a minor system might have an Imperial Ambassador’s yacht, an escort ship and a company of marines, a sub-sector Duke will generally have a massive war fleet. Once the person leaves the position the assets that came with the title are lost.

4) Hereditary Imperial Title

Although the system is designed not to be hereditary at various times and places hereditary titles were granted generally due to a temporary weakness of central Imperial authority. Once given they are hard to get back although the imperial center tries whenever it can.

5) Hereditary non-Imperial Title

In some situations the rulers of a system incorporated into the Imperium may have been given an honorary title. The power and authority of the family depends on their local power base and has no imperial backing. The title is a status and courtesy thing (but may include perks like right to bear arms and huscarls).


Noble Perks

The standard Boyar perks are the right to bear arms and a fee (land and income) if hereditary. Further fees can include the right to armed household retainers known as “Huscarls”.

Further fees can be taken from a random table from issue #2 found here

Noble Careers

Using this char gen  shoul dhave two noble careers.

1) An independent noble with lots of varied skill tables to choose from from farming to space exploration to business.

2) An extension of the standard char gen such that a character that reaches a Boyar rank can switch to an Imperial administration career path. This would be a bit like the Roman Cursus Honorarum.

Tech Levels

My 3rd Imperium is more of a Silk Road Empire i.e. ribbons of civilization through space connecting the advanced systems with mysterious shadows to either side of the light. I think this feel requires a lower standard jump capability of around J3. So the Imperial tech standard is TL12 and J3 is the max jump.

The core Imperial worlds may extend into experimental TL13 plus they have Ancients tech of higher TL but those items are the “magic” items of the setting.

The Darrians are TL15 but hide it. (The Darrians are actually guarding a warp gate that leads to another plane where the main Darrian civilization is based.)

As this is an Imperium setting the TL is quasi-universal i.e. all the worlds and colonies that are part of the 3I are partially TL12 in that a lot of critical tech like power supply and habitats are TL12 except in most cases it’s imported and often second hand and spare parts are imported. The TL listed will be an indication of how gravpunk the system is.

Systems with a native population which are isolated from the 3I trade network will have the industrial ability indicated by the TL but will also have some imported TL12.


The primary divisions in tech (partly decided on for the purpose of analyzing govt. types in the UPP stats) are

  • low tech (5-) pre industrial revolution
  • mid tech (6-8) post industrial revolution
  • high tech (9+) space


nb this means systems with higher tech levels in the canon data are assumed to be TL12 but a bit ahead of other systems in one or more areas so

  • TL12 = TL 12
  • TL13 = TL12+
  • TL14 = TL12++
  • TL15 = TL12+++


Tech Levels

The main difference with canon is making J1 start at 10 as I wanted a clear break where 08 is rockets and 09 is the big break through with fusion and grav leading to m-drives and systems being fully colonized before interstellar. Part of that is m-drives and j-drives are staggered i.e. the first M-Drives are TL09 and the first J-Drives TL10.

  • 00 stone age pre-agriculture
  • 01 stone age post agriculture
  • 02 bronze age
  • 03 iron age
  • 04 medieval
  • 05 muskets
  • 06 rifles
  • 07 bombers
  • 08 rockets
  • 09 solar system
  • 10 Jump – pioneer Interstellar
  • 11 Early Interstellar
  • 12 Mature Interstellar – new normal
Power Source
  • 06 Coal
  • 07 Oil
  • 08 Nuclear
  • 09 Fusion
  • 09 Grav, M-Drive (A, B, C, D)
  • 10 J-Drive(A, B, C, D), M-Drive (E, F, G, H)
  • 11 J-Drive(E, F, G, H), M-Drive (J, K)
  • 12 J-Drive(J, K), M-Drive (L, M, N)
Weapons & Armor
  • TL6: rifle
  • TL7: auto-rifle, flak jacket
  • TL8: kinetic weapons, cloth, mesh
  • TL9: laser weapons
  • TL10: combat armor, reflec
  • TL11:
  • TL12: plasma weapons, battle dress


  • flak jacket: heavy armor, partial ballistic cloth
  • cloth: heavy armor, lighter full body ballistic cloth, good vs kinetic, less good vs lasers
  • mesh: light armor, light version of cloth reinforced with internal mesh
  • combat armor: heavy armor, cloth with improved laser resistance
  • reflec: light armor, mesh with improved laser resistance

no TL distinction between laser carbine and rifle

  • carbine: shorter, shorter ranged, more powerful – for shipboard actions
  • rifle: longer, longer ranged, less damage


  • standard civilian = kinetic weapons, cloth or mesh
  • standard military = lasers, combat armor or reflec
  • elite military = plasma, battle dress