It is impossible to accept without considerable reserve the accounts that have come down to us of the force which Antiochus collected. According to Justin, it consisted of no more than 80,000 fighting men, to which was attached the incredible number of 300,000 camp-followers, the majority being composed of cooks, bakers, and actors. As in other extreme cases the camp-followers do but equal or a little exceed the number of men fit for service, this estimate, which makes them nearly four times as numerous, is entitled to but little credit. The late writer, Orosius, corrects the error here indicated; but his account seems to err in rating the supernumeraries too low. According to him, the armed force amounted to 300,000, while the camp-followers, including grooms, sutlers, courtesans, and actors, were no more than a third of the number. From the two accounts, taken together, we are perhaps entitled to conclude that the entire host did not fall much short of 400,000 men. This estimate receives confirmation from an independent statement made by Diodorus, with respect to the number who fell in the campaign—a statement of which we shall have to speak later.
The army of Phraates, according to two accounts of it (which, however, seem to represent a single original authority), numbered no more than 120,000. An attempt which he made to enlist in his service a body of Scythian mercenaries failed, the Scyths being willing to lend their aid, but arriving too late to be of any use. At the same time a defection of the subject princes deprived the Parthian monarch of contingents which usually swelled his numbers, and threw him upon the support of his own countrymen, chiefly or solely. Under these circumstances it is more surprising that he was able to collect 120,000 men than that he did not bring into the field a larger number.