 The earliest textual evidence of the handheld crossbow used in battle dates to the 4th century BC.Handheld crossbows with complex bronze trigger mechanisms have also been found with the Terracotta Army in the tomb of Qin Shihuang (r. 221–210 BC) that are similar to specimens from the subsequent Han Dynasty (202 BC – 220 AD), while crossbowmen described in the Han Dynasty learned drill formations, some were even mounted as cavalry units, and Han dynasty writers attributed the success of numerous battles against the Xiongnu to massed crossbow fire.Tanaka, Norio.