Andrew Harclay, 1st Earl of Carlisle the Scots, under the command of Robert the Bruce, at the Battle of Old Byland in Yorkshire. The English commander, John of Brittany, Earl of Richmond, was taken prisoner, while the king himself barely escaped capture. It was the worst defeat the English had suffered in the wars since the Battle of Bannockburn in 1314. Harclay had received a summons to join the royal army, but had not been able to bring his troops south in time to come to the king's rescue. The event convinced him that the war against Scotland could not be won under the leadership of
Robert the Bruce from English rule (having received a reply to offers of assistance from Donal O'Neil, king of Tyrone), and to open a second front in the continuing wars with England. Bruce was even crowned as High King of Ireland in 1316. Robert later went there with another army to assist his brother. In conjunction with the invasion, Bruce popularised an ideological vision of a "Pan-Gaelic Greater Scotia" with his lineage ruling over both Ireland and Scotland. This propaganda campaign was aided by two factors. The first was his marriage alliance from 1302 with the de Burgh family of the Earldom of