Author: Duncan Head
Scale: one element to 300 men
1-2 Roman legions, each of:
Hastati, Reg Bd (O) or (F) 4-6
Principes, Reg Bd (O) 1 per Roman hastati
Velites, Reg Ps (S) 1 per Roman hastati
Triarii, Reg Sp (S) 2
Cavalry, Reg Cv (O) 0-1
1-2 Latin legions or allied alae, each of:
Hastati, Reg Bd (I) 4-8
Principes, Reg Bd (I) 1 per allied hastati
Velites, Reg Ps (S) 1 per allied hastati
Triarii, Reg Sp (O) 2
Cavalry, Reg Cv (O) 2-3
Upgrade allied infantry to the same as their Roman equivalents Any
Replace allied infantry with lighter-equipped types, Reg Ax (I) 0-half
Replace allied cavalry with Tarantines, Reg LH(O) 0-1
Before 211:
Replace velites with leves, Reg Ps (I) All or none
Notes:
There must be the same number of allied legions/alae as Roman
legions, and at least as many allied infantry as Roman infantry.
Allied infantry not replaced by Ax must follow the proportions
defined (or some wording that works, so you can't just replace all
the Sp, say).
Later in another post (number 3552) he amended the list to this:
1-2 Latin legions or allied alae, each of:
Hastati, Reg Bd (I) 3-6
Principes, Reg Bd (I) 1 per allied hastati
Velites, Reg Ps (S) 1 per allied hastati
Triarii, Reg Sp (O) 2
Equites, Reg Cv (I) or (O) 2
Upgrade allied infantry to the same as their Roman equivalents Any
Replace Allied Infantry with lighter-equipped types, Reg Ax (I) 0-half
Pedites extraordinarii, up to 1/3 Reg Ps (S), the rest all Reg Bd (F) or all Reg Bd (O) or all Reg Ax (S) 0-1 per 4 other allied foot
Equites extraordinarii, Reg Cv (O) 1 per 2 other allied equites
Replace allied or extraordinarii equites with Tarantines, Reg LH (O) 0-1
The reduced numbers of allied ala foot are to allow for the extraordinarii being listed separately. The constraint that there must be as many allied foot as Roman prevents you from using the minimum 3-of-everything if you don't use the extraordinarii option. The extraordinarii Ps option allows for the possibility that they may have been a bit of eveything.
All infantry of a given legion or ala must be in the same command, except that Ps may be in a different command to support Cv, and all the army's triarii may be detached to the same command as the baggage. Extraordinarii may be in any command (in the Livy 34 passage I quoted, the extraordinarii are split between two gates, so may be in two commands).
See also Luke Ueda-Sarson's alternative late republic list at http://www.ne.jp/asahi/luke/ueda-sarson/MarianDBM.html which overlaps with the end of the published Polybian list.