The Roman deity Mars pictured, at right, on the coin of Roman Emperor Aemilianus, in AD 253. Mars was the Roman God of War, the son of Juno and Jupiter. As the word Mars has no Indo-European derivation, it is most likely the Latinized form of the agricultural Etruscan god Maris. Initially, the Roman god of fertility and vegetation and a protector of cattle, fields and boundaries, Mars later became associated with battle and identified with the Greek god Ares.