In December, Edward led his army across the River Severn and advanced into the Welsh Marches, where the opposition forces had gathered. The coalition of Marcher Lords crumbled and the Mortimers surrendered to Edward, but Damory, Audley, and the Earl of Hereford marched north in January to join Lancaster, who had laid siege the king's castle at Tickhill. Bolstered by fresh reinforcements from the Marcher Lords, Edward pursued them, meeting Lancaster's army on 10 March at Burton-on-Trent. Lancaster, outnumbered, retreated without a fight, fleeing north. Andrew Harclay cornered Lancaster at the Battle of Boroughbridge, and captured the earl. Edward and Hugh the Younger met Lancaster at Pontefract Castle, where, after a summary trial, the earl was found guilty of treason and beheaded. Edward and the Despensers Edward punished Lancaster's supporters through a system of special courts across the country, with the judges instructed in advance how to sentence the accused, who were not allowed to speak in their own defence. Many of these so-called "Contrariants" were simply executed, and others were imprisoned or fined, with their lands seized and their surviving relatives detained. The Earl of Pembroke, whom Edward now mistrusted, was arrested; he was released only after pledging all his possessions as collateral for his own loyalty. Edward was able to reward his loyal supporters, especially the Despenser family, with the confiscated estates and new titles. The fines and confiscations made Edward rich: almost £15,000 was brought in during the first few months, and by 1326, Edward's treasury contained £62,000. A parliament was held at York in March 1322 at which the Ordinances were formally revoked through the Statute of York, and fresh taxes agreed for a new campaign against the Scots. The English campaign against Scotland was planned on a massive scale, with a force of about 23 thousand men. Edward advanced through Lothian towards Edinburgh, but Robert the Bruce declined to meet him in battle, drawing Edward further into Scotland. Plans to resupply the campaign by sea failed, and the large army rapidly ran out of food. Edward was forced to retreat south of the border, pursued by Scottish raiding parties. Edward's illegitimate son, Adam, died during the campaign, and the raiding parties almost captured Isabella, who was staying at Tynemouth and was forced to flee by sea. Edward planned a fresh campaign, backed by a round of further taxes, but confidence in his Scottish policy was