Albert Barnes Commentary 2 Chronicles 26:15

"And he made in Jerusalem engines, invented by skilful men, to be on the towers and upon the battlements, wherewith to shoot arrows and great stones. And his name spread far abroad; for he was marvellously helped, till he was strong." — 2 Chronicles 26:15 (ASV)

Uzziah’s engines seem to have corresponded to the Roman ballista and catapult, respectively. The ballista, which threw stones, was known to the Assyrians as early as the time of Sardanapalus I, the contemporary of Jehoshaphat. The catapult is not represented on either the Assyrian or the Egyptian sculptures. On the whole, it seems most probable that both kinds of engines were invented in Assyria and introduced from there into Palestine.