After clearing the English out of Scotland, Wallace turned his mind to the administration of the country. One of his early intentions was to reestablish commercial and diplomatic ties with Europe and win back the overseas trade that Scotland had enjoyed under Alexander III. Any evidence of his administrative acumen was probably destroyed by Edward's officials after Wallace's execution. There is, however, one Latin document in the archives of the Hanseatic town of Lübeck, which was sent on 11 October 1297 by "Andrew de Moray and William Wallace, leaders of the kingdom of Scotland and the community of the realm." It told the merchants of Lübeck and Hamburg that they now had free access to all parts of the kingdom of Scotland, which had, by favour of God, been recovered by war from the English.

Only one week after this document was signed, Wallace mounted an invasion of England. Crossing into Northumberland, the Scots followed the English army fleeing south in disarray. Caught between two armies, hundreds of refugees fled to safety behind the walls of Newcastle. The Scots laid waste a swathe of countryside before wheeling west into Cumberland and pillaging all the way to Cockermouth, before Wallace led his men back into Northumberland and fired 700 villages. On his return from England, laden with booty, Wallace found himself at the pinnacle of his power.