Henry experienced a rather more inconsistent relationship with King Richard II than his father had.
First cousins and childhood playmates, they were admitted together to the Order of the Garter in 1377, but Henry participated in the Lords Appellants' rebellion against the king in 1387.
After regaining power, Richard did not punish Henry, although he did execute or exile many of the other rebellious barons.
In fact, Richard elevated Henry from Earl of Derby to Duke of Hereford.

Henry spent the full year of 1390 supporting the unsuccessful siege of Vilnius (capital of the Grand Duchy of Lithuania) by Teutonic Knights with 70 to 80 household knights.
During this campaign he bought captured Lithuanian women and children and took them back to Königsberg to be converted.
Henry's second expedition to Lithuania in 1392 illustrates the financial benefits to the Order of these guest crusaders.
His small army consisted of over 100 men, including longbow archers and six minstrels, at a total cost to the Lancastrian purse of £4,360.
Despite the efforts of Henry and his English crusaders, two years of attacks on Vilnius proved fruitless.
In 1392–93 Henry undertook a pilgrimage to Jerusalem, where he made offerings at the Holy Sepulchre and at the Mount of Olives.
Later he vowed to lead a crusade to 'free Jerusalem from the infidel,' but he died before this could be accomplished.

The relationship between Henry and the king met with a second crisis.
In 1398, a remark by Thomas de Mowbray, 1st Duke of Norfolk, regarding Richard II's rule was interpreted as treason by Henry and Henry reported it to the king.
The two dukes agreed to undergo a duel of honour (called by Richard II) at Gosford Green near Caludon Castle, Mowbray's home in Coventry.
Yet before the duel could take place, Richard decided to banish Henry from the kingdom (with the approval of Henry's father, John of Gaunt) to avoid further bloodshed.
Mowbray himself was exiled for life.

John of Gaunt died in February 1399.
Without explanation, Richard cancelled the legal documents that would have allowed Henry to inherit Gaunt's land automatically.
Instead, Henry would be required to ask for the lands from Richard.
After some hesitation, Henry met with the exiled Thomas Arundel, former Archbishop of Canterbury, who had lost his position because of his involvement with the Lords Appellant.
Henry and Arundel returned to England while Richard was on a military campaign in Ireland.
With Arundel as his advisor, Henry began a military campaign, confiscating land from those who opposed him and ordering his soldiers to destroy much of Cheshire.
Henry initially announced that his intention was  to reclaim his rights as Duke of Lancaster, though he quickly gained enough power and support to have himself declared King Henry IV, imprison King Richard (who died in prison under mysterious circumstances) and bypass Richard's 7-year-old heir-presumptive, Edmund de Mortimer, 5th Earl of March.
Henry's coronation, on 13 October 1399 at Westminster Abbey, may have marked the first time since the Norman Conquest when the monarch made an address in English.

Henry consulted with Parliament frequently, but was sometimes at odds with the members, especially over ecclesiastical matters.
On Arundel's advice, Henry obtained from Parliament the enactment of De heretico comburendo in 1401, which prescribed the burning of heretics, an act done mainly to suppress the Lollard movement.
In 1410, Parliament suggested confiscating church land.
Henry refused to attack the Church that had helped him to power, and the House of Commons had to beg for the bill to be struck off the record.
Henry experienced a rather more inconsistent relationship with King Richard II than his father had. First cousins and childhood playmates, they were admitted together to the Order of the Garter in 1377, but Henry participated in the Lords Appellants' rebellion against the king in 1387. After regaining power, Richard did not punish Henry, although he did execute or exile many of the other rebellious barons. In fact, Richard elevated Henry from Earl of Derby to Duke of Hereford.
Henry spent the full year of 1390 supporting the unsuccessful siege of Vilnius (capital of the Grand Duchy of Lithuania) by Teutonic Knights with 70 to 80 household knights. During this campaign he bought captured Lithuanian women and children and took them back to Königsberg to be converted. Henry's second expedition to Lithuania in 1392 illustrates the financial benefits to the Order of these guest crusaders. His small army consisted of over 100 men, including longbow archers and six minstrels, at a total cost to the Lancastrian purse of £4,360. Despite the efforts of Henry and his English crusaders, two years of attacks on Vilnius proved fruitless. In 1392–93 Henry undertook a pilgrimage to Jerusalem, where he made offerings at the Holy Sepulchre and at the Mount of Olives. Later he vowed to lead a crusade to 'free Jerusalem from the infidel,' but he died before this could be accomplished.
The relationship between Henry and the king met with a second crisis. In 1398, a remark by Thomas de Mowbray, 1st Duke of Norfolk, regarding Richard II's rule was interpreted as treason by Henry and Henry reported it to the king. The two dukes agreed to undergo a duel of honour (called by Richard II) at Gosford Green near Caludon Castle, Mowbray's home in Coventry. Yet before the duel could take place, Richard decided to banish Henry from the kingdom (with the approval of Henry's father, John of Gaunt) to avoid further bloodshed. Mowbray himself was exiled for life.
John of Gaunt died in February 1399. Without explanation, Richard cancelled the legal documents that would have allowed Henry to inherit Gaunt's land automatically. Instead, Henry would be required to ask for the lands from Richard. After some hesitation, Henry met with the exiled Thomas Arundel, former Archbishop of Canterbury, who had lost his position because of his involvement with the Lords Appellant. Henry and Arundel returned to England while Richard was on a military campaign in Ireland. With Arundel as his advisor, Henry began a military campaign, confiscating land from those who opposed him and ordering his soldiers to destroy much of Cheshire. Henry initially announced that his intention was  to reclaim his rights as Duke of Lancaster, though he quickly gained enough power and support to have himself declared King Henry IV, imprison King Richard (who died in prison under mysterious circumstances) and bypass Richard's 7-year-old heir-presumptive, Edmund de Mortimer, 5th Earl of March. Henry's coronation, on 13 October 1399 at Westminster Abbey, may have marked the first time since the Norman Conquest when the monarch made an address in English.
Henry consulted with Parliament frequently, but was sometimes at odds with the members, especially over ecclesiastical matters. On Arundel's advice, Henry obtained from Parliament the enactment of De heretico comburendo in 1401, which prescribed the burning of heretics, an act done mainly to suppress the Lollard movement. In 1410, Parliament suggested confiscating church land. Henry refused to attack the Church that had helped him to power, and the House of Commons had to beg for the bill to be struck off the record.
Henry IV of England