Kingdom of Scotland 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 in 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 its fall in 1318. After the establishment of Scottish independence, Robert
Robert the Bruce appear not to have expected the Scots to give battle here, and as a result had kept their forces in marching, rather than battle, order, with the archers − who would usually have been used to break up enemy spear formations − at the back, rather than the front, of the army. The English cavalry found it hard to operate in the cramped terrain and were crushed by Robert's spearmen. The English army was overwhelmed and its leaders were unable to regain control. Edward II was dragged from the battlefield, hotly pursued by the Scottish forces, and only just escaped