 Perseus of Macedon used artillery in the Third Macedonian War to defend the Elpeus river from Aemilius Paulus, who did indeed move away to seek another route around this defensive line.It was also used in fortified towns to harass enemy assailants.Its use in the battlefield does not seem to have been important, as mass use is not attested until much later, as Arrian clearly suggests in his ""Array against the Alans"".