 To maintain the siege and defend against the reinforcements, Caesar formed a line of fortifications on both sides, and they played an important role in his victory.Lilies were also used by Scots against the English at the Battle of Bannockburn in 1314, and by Germans at the Battle of Passchendaele in the First World War.A more easily deployed defense used by the Romans was the caltrop, a weapon about 12–15 cm across with four sharp spikes that are oriented so that when it is thrown on the ground, one spike always points up.