Henry IV, Part 1, culminates in the battle of Shrewsbury between the king’s army and rebels seeking his crown. The dispute begins when Hotspur, the son of Northumberland, breaks with the king over the fate of his brother-in-law, Mortimer, a Welsh prisoner. Hotspur, Northumberland, and Hotspur’s uncle Worcester plan to take the throne, later allying with Mortimer and a Welsh leader, Glendower.