DRAMATIS PERSONAE
KING HENRY IV
PRINCE HAL – later King Henry V
PRINCE JOHN OF LANCASTER – Henry's son
DUKE OF GLOUCESTER – Henry's son
DUKE OF CLARENCE – Henry's son
Usually referred to as “Hal” in the play, the historical Harry lived from 1387 to 1422, and became Henry V (depicted in the  eponymous play ) in 1413. 
 
 King Henry V, artist unknown, via  Wikimedia Commons. 
 Hal’s journey from drunken layabout to conquering king is in many ways the common concern of the latter three plays of the second tetralogy: he’s mentioned in passing at  the end of  Richard II ,  but goes on to ascend to the throne at the  end of this play.  He’s structurally important, too: the play oscillates from high-minded scenes at court to low-minded ones in Eastcheap, with Hal as the connection.
Henry IV Part 2 Characters of the Play