A “recitation” session is generally a regularly scheduled classroom session that is not led by the professor or lecturer but by a teaching assistant (TA). These are along the same lines as a “lab” sessions used alongside Chemistry or Physics lectures.

May be it is an Americanism, never heard of the word used in that manner before(as a non American).

In Commonwealth countries at least, some synonyms for recitation are “tutorial” or “study group”.

I think it is rather an American tradition, and it's not not even present at every university here (or at least by that name), but it's also not recent. I've found references going at least to the 1910s.

And “came to” or “came in to” are equivalent to “attended”

In many schools/universities in the US, recitation is a kind of discussion class where a small number of students attend for more focused problem-solving/teaching