Warfare in Medieval Scotland and supply his armies. Part of the reason for Robert I's success was his ability to call on naval forces from the Islands. As a result of the expulsion of the Flemings from England in 1303, he gained the support of a major naval power in the North Sea. The development of naval power allowed Robert to successfully defeat English attempts to capture him in the Highlands and Islands and to blockade major English controlled fortresses at Perth and Stirling, the last forcing Edward II to attempt the relief that resulted at English defeat at Bannockburn in 1314. Scottish naval
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