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Converting Worlds from Milieu 1100 to Milieu 0

This article was originally posted to the pre-magazine website in 1996 and reprinted in the May/June 2019 issue.

This process is designed to convert the old Classic or Mega Traveller year 1100 worlds to something that should plausibly represent the worlds as they were in Year 0. If you want to use this to create your own Milieu 0/First Survey sectors, go right ahead. Personally, I am using them for the “GM’s Playgrounds” of Zarushagar, Fornast and Delphi sectors, which will not have anything published by Imperium Games (so claims First Survey), but did have data published by GDW.

Bear in mind that these rules could probably use some adjustment; I invite any comments or additions you may have.

  1. First, find the tech level for all former Vilani Empire/Rule of Man worlds (which is most of what the Imperium has gotten to by now). The documented maximum TL is 13, so reduce anything higher than that to 13 (D); if you want a higher tech world, that’s your prerogative.
  2. Now that your world’s tech has been capped off, or left alone if not greater than 13, it’s time to retrogress that tech level.
    If current TL is... Subtract...
    10-13 (A-D) 1D6
    7-9 1D3 (or 1D6 / 2, round up)
    0-6 no change
  3. Now use the TL reduction to degrade the starport.
    If the tech level was reduced by... Reduce the starport class by...
    1 no change
    2 1 (A to B, B to C, etc.)
    3-4 2 (A to C, B to D, etc.)
    5-6 3 (A to D, B to E, etc.)

    Special note: Personally, I don’t like the idea of low tech societies (i.e., non-stellar or non-space-faring) without interstellar contact having high level starports. If you wish to incorporate this idea in your retrogression, use this rule:

    If the world is in the Imperial Sphere (i.e., claimed by the 3rd Imperium) leave the starport as you have it now at this stage.

    If the world has been contacted(i.e., within the merchant or scout contact areas), cap off the Starport using this chart:

    If the Tech Level is... The Starport should be no better than...
    7-8 C
    6 D
    5 E

    If the world has not been contacted, reduce the Starport Caps by one additional level (D, E, X)

    Again, if you want to make a world that has a higher level starport, go ahead; I would suggest it be part of a Pocket Empire, though.

  4. Next, figure population: For those worlds that have reliable tech levels needed for surviving on a harsh world, you don’t need to worry about "maximum sustainable population". Those TLs are 7+ for tainted atmospheres, and 9+ for Exotic, Corrorsive, or Insidious atmospheres. If you have a world with these atmosphers, and the TL has been reduced below the indicated levels, ‘nuke’ the world (make it X---000-0 Ba).

    Find the maximum sustainable population for TL 7- worlds; I used the same method that Traveller: The New Era used for preparing a world for the Collapse:

    Assume that the maximum sustainable population for the world is code A (billions), then

    If the following condition is met... reduce the maximum sustainable population by...
    Size 4- 2
    Size 5-7 1
    Atmosphere 4 2
    Atmosphere 5, 7, or 9 1
    Hydrographics 0 2
    Hydrographics 1-2 1
    Hydrographics A 1

    This gives a cap for population of a lower tech world; I assumed that higher tech levels could sustain more people, and TL 8 or 9 should be sufficiently reliable to sustain life in any planetary environment.

  5. Next, reduce the population to account for 1100 years of population reduction: Subtract the tech level reduction from the world population multipler. If that would result in a population multiplier of 0 or less, reduce the population code by 1 and add 10 to the population multiplier, then do the subtraction.

    If the resulting population code is 5 or less, reduce the tech level by one more point; if either the population or tech reduction would also require reducing the starport class as well, do it.

  6. Now, the only thing left to do is determine the government and law level codes. Use the reduced population figure to find the government and law levels as you would for a newly generated world:

    Gov= population-7 + 2d6
    Law=Gov-7 +2d6.

  7. Next, determine the presence of Naval and Scout bases. Ignore Year 1100 data, and recalculate with the new retrogressed starport using the basic world building rules:

    A Naval Base will only appear at a class A or B starport, only on 8+ on 2D6.

    A Scout Base will appear on 7+ on 2D6 at a class D starport, 8+ at a class C starport, 9+ at a class B starport, and 10+ at a class A starport. Scout Bases do not appear at class E or X starports.


1100 data: Shalishii A584998-F Im 310 G2V

Shalishii is in Vland sector, in an area actively claimed by the Third Imperium in Milieu 0.

  1. Cap the world’s tech level: Since the 1100 TL of F (15) is higher than D (13) reduce it:
    A584998-D Im 310 G2V
  2. Since the reduced tech level is still greater than 10, reduce it by 1D6; I roll a 4:
    A584998-9 Im 310 G2V
  3. Reduce the starport. Since the tech level was reduced by 4, reduce the starport by 2 steps:
    C584998-9 Im 310 G2V

    This world is in Imperial space (Vland sector) and its tech level is high enough to support the current starport, so no further reduction in the Starport is necessary.

    This world also has a high enough tech level to avoid a population cap due to environment, so there is no need to cap the population. (If the tech level had been 7-, the maximum sustainable population would be 9, due to size 5)

  4. Reduce the population multiplier by 4: 3-4 is -1; reduce the population code by one (to 8) and 10-1 makes the population multiplier a 9:
    C584898-9 Im 910 G2V
  5. Redetermine the government and law levels according to the standard rules: For government, roll 2D6 (result 7) - 7 (result 0) + population (8, result 8); the new government code is 8.
  6. For law level, roll 2D6 (result 9) - 7 (result 2) + government (8, result 10); the new law level is a strict A (and they must have relaxed it somewhat over the next 1100 years).
    C58488A-9 Im 910 G2V
  7. Determine the presence of bases: Since the starport is a class C starport, we do not roll for a Naval Base. We do roll for a Scout Base; since we have a class C starport, we need to roll 8+ on 2D6; we roll 5, and there is no Scout Base present either.

Now we have our downgraded world:

Year 0: Shalishii C58488A-9 Im 910 G2V
Year 1100: Shalishii A584998-F Im 310 G2V