Henry IV begins with a meeting called by Henry IV at his palace in London. He believes that after a long period of civil war, peace has finally been established. He therefore hopes that his plan to take an English army to the Holy Land to reclaim it from the infidels can now be put into action.
But Westmoreland announces some bad news that forces the king to put his plans on hold. A Welsh chieftain named Owen Glendower has captured Mortimer, the Earl of March, and killed a thousand of his men. Westmoreland also has more unwelcome news, this time from Scotland, where Henry Percy (known as Hotspur), an ally of the King, is involved in a battle at Holmedon with Archibald, Earl of Douglas, the Scottish leader. The messenger who brought this news to Westmoreland left the scene of the battle before the result was known.
But the King has better news. Sir Walter Blunt has just arrived from Holmedon. Hotspur was victorious. Ten thousand Scots were killed, and Hotspur took several Scottish noblemen prisoner.
But there is also sadness in this news for the King. While Northumberland's son, Hotspur, is winning glory on the battlefield, Henry IV's own son, Prince Hal, is living a wild, irresponsible life. The King wishes that the two had been switched at birth, so Hotspur might have been his own son. But there is also a problem for the King regarding Hotspur. He has much pride, and has sent word to the King that he intends to keep all but one of his prisoners for his own purposes, rather than handing them over to the King. Westmoreland tells the King that Worcester, Hotspur's uncle, has put him up to it, since Worcester opposes the King.
The King says he has sent for Hotspur so he can explain himself in person. He announces a meeting of his council at Windsor the following Wednesday.
The historical Henry IV ascended to the throne in 1399, after deposing his younger cousin, Richard II. But his claim to be King was not considered to be a particularly strong one, and other English nobles thought they had just as much right to be King as he. Henry's reign was therefore a stormy one. He escaped an assassination attempt in 1400, and executed those responsible for the plot. Wars soon broke out in Scotland and Wales. The Percy family was a powerful one, and was responsible for defending England's border with Scotland. When Hotspur inflicted a major defeat on the Scots at Holmedon Hill in 1402, Henry IV decided that he could not afford to let the Percy family get too powerful. He therefore demanded some of the spoils of the victory, including the prisoners taken by Hotspur.
This is the historical background for the first scene, which also introduces the theme of the wild Prince Hal, who is a disappointment to his father. The scene also introduces the contrast between Hotspur, who embodies the virtues of honor and martial valor, and Prince Hal, who seems to prefer an irresponsible life lived in low company.