Index Card #23 the ballista

the roman engineers wanted a bigger machine with a greater range so in 399 bc, they invented the ballista. the ballista was unlike the greek onager or trebuchet, built almost entirely out of wood. the ballista used and older frame type that was much more powerful as arms could travel furter, but it was more expensive and so it was used primarily for a big stone throwing machine. the ballista also had a ratch device on the outside, made out of steel, it was larger than the onage or trebuchet. in fact some of the machines were the biggest ever made in roman