By the early 1400s, Henry Percy, 1st earl of Northumberland, and his son Henry (Hotspur), who held marcher offices in Scotland and Wales,  faced attacks from the rebellion of Owen Glydwr in Wales and also from the Scots, whom the Percies defeated at the battle of Homildon Hill in 1402. Having already petitioned the king for more funds to support their efforts and pay their men, they had hoped to ransom their prisoners, including the Scottish leader, Archibald Douglas, as was often allowed by tradition and were dismayed and annoyed when Henry IV instead asserted his right to the prisoners being handed over to the crown. Hotspur refused; he had also been upset by Henry IV’s refusal to ransom his brother-in-law, Edmund Mortimer, who had been captured by Glyndwr, and the Percies subsequently entered an alliance with Glydwr, Mortimer, and their prisoner Douglas to replace the king with the young Earl of March. However, Hotspur was defeated and killed at the battle of Shrewsbury in 1403. Northumberland, who had not been present at Shrewsbury, denied any knowledge of the rebellion and was spared a conviction for treason, although he lost the Wardenships of the two Marches, one of them to his main territorial rival in the north, Ralph Neville, Earl of Westmorland. 

In 1405 Northumberland entered an agreement with Glyndwr and Mortimer, “The Tripartite Indenture”, to remove Henry IV and divide England and Wales between them. He was joined in rebellion by his friend, Thomas, Lord Bardolph, but after an apparent pre-emptive move in which they failed to capture the Earl of Westmorland they fled to Scotland. Proclaimed traitors, their lands were confiscated. 

After a couple of years in exile, Northumberland and his allies prepared to oppose the king one more time. Choosing the winter of 1407/08, they perhaps hoped to catch the king unawares. Chroniclers Adam Usk and the Scotichronicon of William Bower refer to Northumberland as having been lured south by false promises of support, Bower citing the encouragement of Richard (sic) Rokeby, who told the earl “Englishmen would flock to him”, only for Rokeby himself to lead the royal forces against Northumberland.

Northumberland and Bardolph gathered a force comprised of lowland Scottish knights and Northumbrians and marched south. They were joined by at least two important churchmen, the Bishop of Bangor and the Abbot of Hailes.  On arrival at Thirsk, they issued a proclamation that invited people to rise and support them against unjust oppression by the crown. The response was not that anticipated, and of those who joined them few possessed any military experience. By mid-February 1408 news of the rebellion had reached the king, who ordered forces to be raised against them and began to move north himself. The rebels intended to cross the River Nidd at Knaresborough, but found their way was blocked by a royal army comprised of local levies and trained retinues under Sir Thomas Rokeby, the High Sheriff of Yorkshire They were forced east before they could continue south, via Wetherby, and on to Tadcaster, a few miles away. The Sheriff followed them and set watches of guards around Tadcaster to prevent any rebel movement out of this area, and with their whereabouts now common knowledge the rebel leaders decided to make a stand on Bramham Moor, according to tradition on the high ground at Camp Hill.