Royal Scots Navy 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 King Edward II to attempt the relief that resulted at English defeat at Bannockburn in 1314. Scottish naval forces allowed invasions of the Isle of Man in 1313 and 1317 and Ireland in 1315. They were also crucial in the blockade of Berwick, which led to
Robert the Bruce the heavy fighting. The historian Roy Haines describes the defeat as a "calamity of stunning proportions" for the English, whose losses were huge. In the aftermath of the defeat, Edward retreated to Dunbar, then travelled by ship to Berwick, and then back to York; in his absence, Stirling Castle quickly fell. Freed from English threats, Scotland's armies could now invade northern England. Bruce also drove back a subsequent English expedition north of the border and launched raids into Yorkshire and Lancashire. Buoyed by his military successes, Bruce's forces also invaded Ireland in 1315, in an attempt to free the country