Edward II was not his father. Where Edward I had conquered Wales and nearly subdued Scotland, his son lost battles, alienated his barons, and lavished power on favorites. The worst of these, in the eyes of the English nobility, was the Despenser family: Hugh the younger and his father of the same name, whose greed for land and influence united the baronial opposition. Thomas, Earl of Lancaster, Edward's cousin and the richest man in England after the king, became the leader of that opposition. Through the Ordinances of 1311, Lancaster and his allies tried to impose limits on royal authority. By 1321, the conflict had escalated into open rebellion. The marcher lords rose first, and for a brief moment Edward was forced to exile the younger Despenser. But the exile lasted weeks, not months. The king recalled his favorite, crossed the River Severn with an army, and began picking off the rebels one by one. Lancaster, who had remained passive while his allies were crushed, found himself suddenly alone.

Lancaster fled north, hoping to reach Scotland and continue the fight from beyond the border. His army reached Boroughbridge on 16 March and found Andrew Harclay already there, blocking the crossing with levies from Cumberland and Westmorland. Harclay had been a loyal servant of the king, and Lancaster's attempts to negotiate a passage were refused. The situation was straightforward: the rebels needed to cross the River Ure, and the only ways across were the bridge and a ford somewhere nearby. Harclay deployed his men on foot to hold both. Lancaster divided his force into two columns. The Earl of Hereford and Roger de Clifford led one column against the bridge on foot. Lancaster himself took the other toward the ford on horseback. Both attacks failed. On the bridge, Hereford was killed by a spear thrust from below, a wound that would become infamous in the retelling. Clifford was badly wounded, and the column fell apart. At the ford, Lancaster's cavalry never even reached the water. Harclay's longbowmen, veterans of the Scottish wars, cut them to pieces before they could close. The rebel army retreated into the town and spent a miserable night negotiating a surrender that everyone knew was coming.

Lancaster was taken to Pontefract Castle, which had already fallen to the king. There, before a gathering of earls and barons, he was subjected to a show trial. The sentence was death. On 22 March 1322, six days after Boroughbridge, Lancaster was led from the castle and beheaded before a jeering crowd. Some thirty of his followers were also executed. Clifford, who had survived his wounds at the bridge, was hanged from a tower in York that still bears his name. The scale of the reprisals was meant to send a message, and it did. But the aftermath took unexpected turns. A cult grew up around Lancaster, venerating him as a martyr and even a saint. He had shown no particular piety in life. The cult was less about Lancaster's virtues than about Edward's vices.

Harclay was richly rewarded: created Earl of Carlisle, granted lands worth a thousand marks a year. But he was no great admirer of the king. As Warden of the Scottish Marches, he grew frustrated with Edward's refusal to deal with the Scottish threat, and eventually negotiated his own unauthorized peace treaty with the Scots. It was treason. Early in 1323, Harclay was arrested and hanged, drawn, and quartered. The man who had won the king's battle at Boroughbridge died a traitor's death. As for Edward II, his dependence on the Despensers grew only deeper. Lancaster's surviving supporters, including Roger Mortimer, fled to Paris and joined forces with Edward's estranged wife, Isabella. In 1327, Isabella and Mortimer staged a coup. Edward was deposed and his son crowned as Edward III. Boroughbridge today is a quiet market town on the A1 road, the ancient crossing still there, the river still flowing beneath. A battle cross stands in nearby fields. The tactics that Harclay borrowed from the Scots would soon be refined further: at Crecy, at Poitiers, at Agincourt. The longbow was just getting started.