DRAMATIS PERSONAE
KING RICHARD THE SECOND
QUEEN ISABEL, Duchess of York, wife to King Richard
JOHN OF GAUNT, Duke of Lancaster - uncle to the King
EDMUND LANGLEY, Duke of York - uncle to the King
HENRY BOLINGBROKE, Duke of Hereford, son of John of Gaunt, afterwards King Henry IV
DUKE OF AUMERLE, son of the Duke of York
DUCHESS OF GLOUCESTER, widow of Thomas of Woodstock, DUKE OF GLOUCESTER (uncle to King Richard)
The historical Langley (1341-1402), fifth son of Edward III, Duke of York and named after his birthplace in Hertfordshire,  seemed to prefer hunting to power struggles, but the House of York (who would fight the House of Lancaster, tracing their origin back to  John of Gaunt  in the  Wars of the Roses. ) 
 Edmund is eventually persuaded to side with Henry Bolingbroke against his nephew  the King,  so that he can get back the lands Richard took from him after the death of  John of Gaunt.  Following Bolingbroke’s ascension as Henry IV, Edmund discovers a plot by his son Aumerle to assassinate the new king. Aumerle is pardoned by Henry. 
 
 Edmund of Langley, artist unknown,  via.
Richard II Characters of the Play