       DRAMATIS PERSONAE
KING HENRY THE SIXTH
DUKE OF GLOUCESTER, uncle to the King, and Protector
DUKE OF BEDFORD, uncle to the King, and Regent of France
THOMAS BEAUFORT, DUKE OF EXETER, great-uncle to the king
HENRY BEAUFORT, great-uncle to the King, BISHOP OF WINCHESTER,and afterwards CARDINAL
Humphrey, Duke of Gloucester was the youngest son of  Henry IV.  He has a small part in  2 Henry IV ,  but he has a major role in this play, acting as Protector of England. 
 
 Humphrey, Duke of Gloucester in a 15th century drawing. Image via  Wikipedia Commons.
Henry VI Part 1 Characters of the Play