FitzWarin was made constable of Urquhart Castle following the English invasion of Scotland in 1296. Alarmed at the rebellion led by Andrew Moray, the English appointed sheriff of Inverness, Reginald le Chen ordered his principal lieutenants, including FitzWarin to a meeting at Inverness Castle on 25 May 1297 to discuss how to deal with Andrew Moray.[1] After the meeting FitzWarin returned to Urquhart Castle accompanied by his escort of men-at-arms. A few miles south of Inverness, his party was ambushed by a force led by Andrew Moray and Alexander Pilche. With the loss of a number of men and horses, FitWarin was fortunate to escape with his life to the safety of Urquhart Castle. The next day the castle was besieged by Moray, who demanded its surrender.
Euphemia, the Countess of Ross unexpectedly arrived on the scene with her retinue. The countess, whose husband was held by King Edward I of England in the Tower of London,[2] advised Moray to surrender. Moray refused, however she did not move against Moray. Although her advice was ignored, her actions were later commended to the king by FitzWarin. Moray, with no heavy siege equipment available to him, tried to take the castle in a night attack and having failed, was forced to abandon the siege. He left FitzWarin in possession of the castle. Following the siege, FitzWarin wrote to King Edward in July 1297: "Some evil disposed people have joined Andrew Moray at the castle ofAvoch in Ross." Urquhart Castle was again besieged by Andrew Moray and with little supplies the castle garrison was eventually starved into submission.