As the Earl of Darby, Henry entered the House of Lords in 1385. In 1387 he supported his uncle Thomas, Duke of Gloucester, in his opposition to Richard II. (Gloucester was also Richard’s uncle, and Henry was the King’s First cousin. )While taking part in the ‘Merciless’; Parliament of 1388, Henry regained the favor of the King and in 1390 departed on the Crusade to Lithuania and then to Jerusalem. Visiting the kings of Bohemia and Hungary and the Archduke of Austria and then Venice in 1392-1393, he went only as far as Rhodes and then returned to England as a popular hero. He soon entered the government; he served on the Council while Richard was absent in Ireland in 1395 and for his efforts was made Duke of Hereford in 1397.
Henry soon quarreled with the Duke of Norfolk, each accusing the other of arranging the murder of the Duke of Gloucester and calling for a trial by battle. Both men were banished from the realm. Norfolk for life and Henry for 10 years with a proviso that he would be allowed to inherit from his father. But on the death of John of Gaunt in 1399, the Lancastrian estates were confiscated by the King, and Henry decided to return, seemingly to claim his promised inheritance. Taking advantage of the King’s absence in Ireland, Henry landed on July 4, 1399, at Ravenspur, near Bridington, where he was soon joined by the northern nobles who were unhappy with the policies of the monarchy.
By the end of the month Henry and his followers had raised an army and marched to Bristol. When Richard returned in August, the royal army started to desert; Henry claimed the throne for himself, and on August 19 he captured Richard near Conway. He then went with his prisoner to London and there, on September 29, Richard abdicated the throne. On October 13 Parliament formally deposed Richard and transferred the crown to Henry.
This parliamentary action had constitutional importance, since it revived the claim that Parliament had the power to create monarchs. Prior to his coronation, Henry condemned Richard to imprisonment, where the deposed monarch soon dies, possibly due to starvation. Once on the throne, Henry spent his reign solidifying his position and removing the threat posed by the nobles who supported Richard. Starting in 1400, Henry made expeditions in Scotland against the Duke of Albany and the 4th Earl of Douglas and in Wales against Owen Glendower.
He was an active supporter of the Orthodox Church against the Lollards, and in 1401 De heretico comburendo, one of the most important medieval statues, was passed. In 1402 he married Joan of Navarre, the widow of John V, Duke of Brittany, who survived him without issue. In the north the Percy family rose against the King, but Henry defeated them in July 1403 at Shrewsbury and the following year at Dartmouth. A revolt by the 1st Earl of Northumberland, Archbishop Scrope, and the Earl Marshal was defeated in 1405, and 2 years later the Beauforts’ claims to the throne were ended. By the Battle of Brabham Moor in 1408, the domestic threats to the throne were ended, and Henry could turn his attention to the civil wars in France as well as reforming his household administration.
He was able to defeat an attempt to force him to resign in favor of his more popular son (later Henry V), but his health declined, perhaps because of epilepsy. On March 20, 1413, he was seized with a fatal attack while praying at Westminster Abbey and died in the Jerusalem Chamber. He was buried at Canterbury.