Henry IV was the King of England from 1399 to 1413. He was the first king of the House of Lancaster and played a significant role in the Wars of the Roses, a series of civil wars in England. Henry IV is known for his efforts to stabilize the kingdom after a period of political turmoil and for his involvement in military campaigns. He also faced challenges to his rule, including rebellions and conflicts with rival claimants to the throne. Overall, Henry IV's reign was marked by both achievements and struggles as he sought to maintain his authority and secure the future of the English monarchy.