During the reign of his father Henry IV, Henry gained military experience fighting the Welsh during the revolt of Owain Glyndŵr and against the powerful aristocratic Percy family of Northumberland at the Battle of Shrewsbury. Henry acquired an increasing role in England's government due to the king's declining health, but disagreements between father and son led to political conflict between the two. After his father's death in 1413, Henry assumed control of the country and asserted the pending English claim to the French throne.