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
Battle of Halidon Hill ultimate victor. The Treaty of Northampton in 1328 brought an end to over thirty years of intermittent warfare following the defeat of Edward II by Robert Bruce. Bruce's own death the following year opened up an opportunity for the disinherited, Balliol and the English to invade Scotland once more. In 1332 under the leadership of Edward Balliol, son of King John Balliol, and Henry Beaumont, 4th Earl of Buchan, these men invaded Scotland with the full support of Edward III, defeating the Bruce loyalists at the Battle of Dupplin Moor. Building on this success Balliol was crowned King of Scotland.