Thanks to all for the quick response . Due to the high historical accuracy of this mod my first thinking about it was that i will have to wait until Marian reforms to get siege weapons ... i was not wrong ... It's very hard to assault a big city walls without those units ! ... there wasen't in those ancient times mercenary units specialiced in sieges ?? , i know that in the medieval age there was some mercenary armies specialiced in sieges with their own siege weapons ...

P.D: Yes you can call it ballistae , i just use the word in my own language , sorry . Im from Spain and the English it's not the best , sorry too for any gramatical fault !