In 1377 he was styled Earl of Derby and, in 1380, married Mary de Bohun, a co-heiress of the great earldom of Hereford. He was one of the five lords apellant who, in the Merciless Parliament of 1388, forced Richard II to dismiss the favourites associated with his tyrannical rule. 
Adventurous and enterprising, in 1390 he joined the Teutonic knights fighting in Lithuania and also went to Prussia, Cyprus and on pilgrimage to Jerusalem. To his renown as a fighting man, he added a reputation for generosity, elegance and well-developed literary and musical tastes. 
Returning to the political turmoil of Richard II's court, he regained Richard II's favour and, in 1397, was created Duke of Hereford. In 1398 he quarrelled with one of the other former lords appellant, Thomas Mowbray, 1st Duke of Norfolk, and attempted to fight a duel with him. Richard II, increasingly suspicious of Henry, banished him for ten years. 
In 1399, when Henry's father died and Richard II confiscated his vast Lancastrian estates, the exiled Henry found himself at the head of Richard II's growing band of enemies who had suffered similar wrongs. In 1399, while the king was campaigning in Ireland, Henry invaded England. Richard II was forced to abdicate on his return and was imprisoned at Pontefract Castle where he died in 1400, presumed murdered. 
Henry, now King Henry IV, had to fight to retain his throne, first against Richard II's supporters; from 1400 to 1408, against the Welsh under Owain Glyndwr; from 1403 to 1408 against the powerful Percy family; and even against Richard Scrope, Archbishop of York. 
In 1394 Mary de Bohun had died, and, on 7 February 1403 in Winchester Cathedral, Henry IV married Jeanne de Navarre, widow of Jean V, Duke of Brittany. In 1405 he had Richard Scrope, Archbishop of York, executed which was a major political blunder. After 1408 Henry IV fell ill with a mysterious disease, perhaps leprosy. Many believed this was God's vengeance for his misdeed against the Archbishop. He became to rely more and more on his eldest son and heir and by 1410 Prince Henry effectively ruled in his ailing father's place. In 1411 the king, perhaps fearing an impending coup, briefly resumed power. However, in 1413 he took to his sickbed once more and died at 
Winchester. 
When told that the chamber in which he was sick was called Jerusalem, he responded: "Lauds be given to the Father of Heaven, for now I know that I shall die here in this chamber, according to the prophecy of me declared, that I should depart this life in Jerusalem." 

Source: Leo van de Pas