The Battle of Otterburn took place some thirty miles north west of Newcastle upon Tyne where the tributary called the Otter Burn joins the River Rede. The Scots led by the Earl of Douglas had sent two armies into northern England and had agreed to meet near Newcastle.The Earl of Northumberland, now too old to take part in any fighting, sent his sons Henry Percy, known as Harry Hotspur, and Ralph Percy to deal with the invasion. When the armies met, Douglas and Hotspur agreed to single hand-to-hand combat, Hotspur lost this fight and attacked the Scots at their encampment. Although the Scots were initially surprised by the attack the English were defeated and both of the Percy brothers were captured. The Earl of Douglas was killed in the battle.

King Henry IV gave his son Prince Henry, the future Henry V, the task of defeating Glyndwr in North Wales. As the boy was only 13 years old, Hotspur a knight and jouster of importance was given the role of guardian over the Prince. Hotspur was the son of Henry Percy the Earl of Northumberland.

After accusing the king of not paying his army, Hotspur resigned his guardianship of the king's son in North Wales and he left to resume fighting the Scots.

The armies of the Percies and the Scots met at Homildon Hill near Wooler in Northumberland. The Scots were defeated and the Scots' leader the Earl of Douglas was captured. Henry IV wanted Douglas handed over but Hotspur refused. Hotspur was angry with the English king who had refused to pay a ransom for Edmund Mortimer who had been captured by Owain Glyndwr and who was a friend of Hotspur's.

The Percies, led by the Earl of Northumberland and Hotspur announced their intent to revolt against Henry IV. They even promised to free the Scots they had captured at the battle of Homildon if the Scots assisted in the revolt. The plan was to join forces with Owain Glyndwr and support the claim of the young Edmund Mortimer 5th Earl of March to the English throne.

Henry IV managed to reach Shrewsbury just before Hotspur arrived and the rebel army had to camp outside the town to the north. The battle lasted all day but it ended when Hotspur was killed.