Page "Battle of the Trebia" Paragraph 20

Livy states the actual number of Roman troops before the battle to have been 18, 000 men, to which were added 20, 000 Italic allies.

Polybius sets the number at 16, 000 and 20, 000 allies, " this being the strength of their complete army for decisive operations, when the consuls chance to be united.

" He does not say that they were united, only that, if they were, these would be their numbers ; that is, 4 Roman legions and 4 allied alae.

Both authors subsequently tack on 4, 000 cavalry, evidently not part of the 36, 000 or 38, 000, from which it may be inferred that the latter were infantry ( a circumstance not stated by the authors ).