Prendergast, who held lands at Cornhill-on-Tweed, Northumberland and Stirlingshire, Scotland, was a member of the English garrison at Berwick Castle in 1311.
[2] With Sir William Keith and Alexander Gray, led a force of around 200 Scottish cavalry, with some difficulty, to force their way across the ruins of the bridge to the northern bank of the Tweed and then make their way into Berwick, in an attempt to relieve Berwick, under siege by an English army led by King Edward III of England.
[4] The Guardian of Scotland Archibald Douglas considered that the town had been relieved and sent messages to Edward III calling on him to depart, threatening that if he failed to do so the Scots army would devastate England.
[4] As a result, Keith, who had taken over the command of the town from Seton, concluded a fresh truce, promising to surrender if not relieved by Tuesday 20 July.
The following day, the Scottish army approached Halidon Hill from the north-west, ready to give battle with the English.