Henry IV of England, born in April 1367, was the son of John of Gaunt, Duke of Lancaster (third son of Edward III), and Blanche of Lancaster. His early life was steeped in the martial tradition, having joined his father on military campaigns in France. As a young man, he was deeply involved in the politico-military escapades of the kingdom and was created Duke of Hereford.

The friction between Henry and Richard II marked the start of a period of political instability. After a dispute involving the Duke of Norfolk, Henry was exiled by Richard. During his exile, Richard extended it for life and confiscated the Lancastrian inheritance. Seeing this as an opportunity, Henry returned to England in 1399 while Richard was on a campaign in Ireland. With substantial support, he was able to seize power, leading to Richard's capture and subsequent mysterious death in Pontefract Castle.

Upon his ascension to the throne as Henry IV in 1399, he became the first monarch from the House of Lancaster. His reign was marked by numerous challenges, including uprisings from the Welsh led by Owain Glyndŵr, confrontations with the Percys in the North, and religious dissent from the Lollards, followers of John Wycliffe. The repeated revolts drained the royal coffers and caused tensions with Parliament over taxation.

In terms of accomplishments, Henry IV managed to consolidate his reign despite the frequent revolts and the questionable legitimacy of overthrowing Richard II. He strengthened ties with France by marrying Mary de Bohun and later Joan of Navarre. His reign witnessed a strengthening of the parliamentary system, with the Commons gaining more voice, largely because of the king's need for taxation to fund his campaigns.

However, his reign was not without its flaws. The manner of his rise to the throne cast a long shadow, causing challenges to his rule. He was accused of being too lenient with enemies and, at the same time, too harsh with allies, leading to discontent.

Henry's personal life was marked by the early death of his first wife, Mary, leaving him with a brood of children, the most famous of whom was the future Henry V. His relationship with his eldest son was complex, marked by both pride and tension, especially when the young prince took on governmental responsibilities during the king's bouts of illness.

By the 1410s, Henry's health deteriorated, suffering from a skin condition, possibly leprosy or psoriasis, and frequent bouts of illness. He passed away in 1413 in the Jerusalem Chamber of Westminster Abbey, a location foretold by a prophecy he apparently took to heart. The English people, at the time of his death, had mixed feelings. While many were relieved, hoping for a more stable reign under his son, Henry V, others would have remembered the usurpation and its subsequent instability.

Society during Henry IV's reign was marked by political intrigue, a continued evolution of the English language, and the growth of a distinctly English culture, even as ties with France remained strong. The period also saw the continuation of the Hundred Years' War and the Peasants' Revolt, though the latter was during Richard II's reign, which helped shape the societal and political landscape of Henry IV's time.