Deconstructing Polybius - an example

[Domen]

Peter, Antiochos was at the head of the cavalry on the Seleucid left, not the phalanx, so in effect you are saying the same thing I said.

You didn't clarify this before. Antiochos was in personal command of Seleucid cavalry (was that really their left wing or right? - I think that was Roman left, but Seleucid right), but at the same time he was the commander in chief of the entire army. So when you said that Antiochos defeated the Romans, I couldn't be sure whether you say about his cavalry or claim that it was his phalanx which defeated the Romans.

And of course not all Roman legions were put to flight but a part of them was although we do not know how many, could have been a legion, could have been more or less.

According to what Justin and Livy write, it could be only one legion (or at most one legion and one ala supporting that legion). And Appian doesn't mention how many, he only writes about the Seleucid cavalry "breaking through the Roman phalanx" (looks like this is very on-topic in this thread).

But Appian writes about breaking through the line, not about breaking (routing) the line, and certainly not about routing the entire Roman line (or the entire Roman army). So it probably was just part of it (as Justin and Livy write, it was just one legion or at most one legion and one supporting ala).

Breaking has two meanings - cracking something in half or routing something.

I would rather check the original word in Appian's account again.

So, as my point was, the phalanx was not beaten by the Roman infantry line, as was the question.

In the end it was beaten - but before that elephants saw confusion among the phalanx.

However, elephants were annoyed by Roman pila / javelins / arrows IIRC.

So Romans caused the fact that those elephants started to run amok, IIRC.