Duke of Lancaster

Dukedom of Lancaster
Arms of Henry of Grosmont: the arms of his grandfather Edmund Crouchback (arms of King Henry III, a label France of three points)
Creation date	1351 (first creation) 1362 (second creation) 1399 (third creation)
Created by	Edward III (first creation) Edward III (second creation) Henry IV (third creation)
Peerage	Peerage of England
First holder	Henry of Grosmont
Last holder	Henry V (merged in the Crown)
Subsidiary titles	First creation Earl of Derby Earl of Leicester Earl of Lancaster Earl of Lincoln Earl of Moray Second creation Earl of Richmond Earl of Leicester Earl of Lancaster Earl of Derby Third creation Earl of Chester (subsidiary of Prince of Wales)
Status	Extinct (merged in the Crown)
Extinction date	1361 (first creation) 1399 (second creation) 1413 (third creation)
Former seat(s)	Lancaster Castle

The dukedom of Lancaster is a former English peerage, created three times in the Middle Ages, which finally merged in the Crown when Henry V succeeded to the throne in 1413. Despite the extinction of the dukedom the title has continued to be used to refer to the reigning monarch of the United Kingdom in relation to the County Palatine of Lancaster and the Duchy of Lancaster, an estate held separately from the Crown Estate for the benefit of the sovereign.^[1]