The Battle of Sandwich, also called the Battle of Dover was on 24 August 1217. It was part of the First Barons' War. A Plantagenet English fleet was led by Hubert de Burgh. This fleet attacked a Capetian French fleet led by Eustace the Monk and Robert of Courtenay off Sandwich, Kent. The English captured the French flagship and many of their supply ships. This forced the French to go back to Calais.