Edward II of England barons banished Gaveston, to which Edward responded by revoking the reforms and recalling his favourite. Led by Edward's cousin, the Earl of Lancaster, a group of the barons seized and executed Gaveston in 1312, beginning several years of armed confrontation. English forces were pushed back in Scotland, where Edward was decisively defeated by Robert the Bruce at the Battle of Bannockburn in 1314. Widespread famine followed, and criticism of the king's reign mounted. The Despenser family, in particular Hugh Despenser the Younger, became close friends and advisers to Edward, but Lancaster and many of the barons seized the Despensers' lands
Robert the Bruce planned a major military campaign with the support of Lancaster and the barons, mustering a large army of between 15,000 and 20,000 men. In the spring of 1314, Edward Bruce laid siege to Stirling Castle, a key fortification in Scotland whose governor, Philip de Mowbray, agreed to capitulate if not relieved before 24 June 1314. In March, James Douglas captured Roxburgh, and Randolph captured Edinburgh Castle, while in May, Bruce again raided England and subdued the Isle of Man. News of the agreement regarding Stirling Castle reached the English king in late May, and he decided to speed his march