Wallace was succeeded as Guardian of the Kingdom jointly by Robert Bruce and John Comyn, but they could not see past their personal differences. This brought another shift in the political situation. During 1299, diplomatic pressure from France and Rome persuaded Edward to release the imprisoned King John into the custody of the Pope. The papacy also condemned Edward's invasions and occupation of Scotland in the Papal bull Scimus, Fili. The bull ordered Edward to desist his attacks and start negotiations with Scotland. However, Edward ignored the bull.

William Wallace was sent to Europe to try to gain further support for the Scottish cause. Wallace went to France to seek the aid of Philip IV, and he possibly went on to Rome. William Lamberton, Bishop of St Andrews, was appointed as a third, neutral Guardian to try to maintain order between Bruce and Comyn. The Scots also recaptured Stirling Castle.

In May 1300, Edward I led a campaign into Scotland, invading Annandale and Galloway. With the success of the English at Falkirk two years earlier, Edward must have felt in a position to bring Scotland under full control permanently. To do this required further campaigning, eliminating the last opposition and securing castles that were (or would be) centres of resistance. The English took control of Caerlaverock Castle, but apart from some small skirmishes, there was no action. In August, the Pope sent a letter demanding that Edward withdraw from Scotland. Due to the lack of success, Edward arranged a truce with the Scots on 30 October and returned to England.