In June 1271, Acre became exposed when Baibars' conquered the Montfort Castle to its north-east. He immediately made an unsuccessful attempt at raid on Cyprus. At that time, the English prince Edward took a small army of about 1,000 men on a a crusade to the Latin East, arriving in Acre on 9 May 1271. Edward was soon disillusioned by the uncooperativeness of the local Christians. Baibars' failed attack on their island had disturbed Cypriot knights, who refused Hugh's summons to serve on the mainland. They argued that the king could not expect them to fight for him outside Cyprus. Edward was called on to arbitrate. Their disobedience was humiliating for Hugh. It was decided that the knights could be commanded to serve abroad for four months each year if led by the king or his son. Edward helped Hugh raid Baibars' territory, and early in 1272 Hugh secured a truce, after which Acre remained at peace until 1291. Edward left on 16 June 1272.