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.
There were three creations of the dukedom of Lancaster during the fourteenth and fifteenth centuries. The first creation was on 6 March 1351 for Henry of Grosmont, 4th Earl of Lancaster, a great-grandson of Henry III; he was also 4th Earl of Leicester, 1st Earl of Derby, 1st Earl of Lincoln and Lord of Bowland. When he died in 1361 the peerage became extinct.
The second creation of the title Duke of Lancaster occurred on 13 November 1362, when it was granted to John of Gaunt, 1st Earl of Richmond and the third surviving son of King Edward III. Gaunt became the son-in-law of Henry of Grosmont through his marriage to Blanche of Lancaster, HenryâÂÂs second daughter and eventual heir.
Upon GauntâÂÂs death on 4 February 1399, the dukedom passed to his son, Henry of Bolingbroke, who had already been created Duke of Hereford. Later that same year, Bolingbroke deposed Richard II and ascended the throne as Henry IV, at which point the Dukedom of Lancaster merged in the Crown. Henry re-created the dukedom on 10 November 1399 for his eldest son Henry of Monmouth, Prince of Wales. In 1413 Monmouth ascended the throne as King Henry V and the dukedom merged in the crown again, where it has remained ever since.
Nevertheless, the title continues to be used to refer to the monarch in relation to Lancashire and the Duchy of Lancaster, the estate associated with the former dukedom. It was customary at formal dinners in the historic county boundaries of Lancashire and in Lancastrian regiments of the armed forces for the Loyal Toast to be announced as "The King, Duke of Lancaster". Traditionally in Lancashire, the national anthem was sung as "God save our gracious King, long live our noble Duke", as it is each Sunday morning in the Savoy Chapel in London, a church attached to the Duchy. However, the legal basis for the sovereign to use the title has been disputed as the right to inheritance of the title only arises upon each creation, which is different than the crown's right to the duchy's estate after the merger. In particular, George V was given legal advice that it was "extremely unlikely" that he was the duke of Lancaster.
| Henry of Grosmont<br />House of Plantagenet<br />' | || <br />Grosmont Castle<br />son of Henry, 3rd Earl of Lancaster and Maud Chaworth|| Isabel of Beaumont<br /><br />2 children | 23 March 1361<br />Leicester Castle<br />aged 50âÂÂ51 |- | colspan="5" | Henry of Grosmont died in 1361 without male issue.
| John of Gaunt<br />House of Lancaster <br />' | | 6 March 1340<br />Ghent<br />son of Edward III and Philippa of Hainault|| Blanche of Lancaster<br />19 May 1359 â 12 September 1368<br />8 children<br />Constance of Castile<br />21 September 1371 â 24 March 1394<br />2 children<br />Katherine Swynford<br />13 January 1396<br />4 children | 3 February 1399<br />Leicester Castle<br />aged 58 |- | Henry Bolingbroke<br />House of Lancaster<br />' | | <br />Bolingbroke Castle<br />son of John of Gaunt and Blanche of Lancaster | Mary de Bohun<br /> â 4 June 1394<br />6 children<br />Joan of Navarre<br />7 February 1403<br />no children | 20 March 1413<br />Westminster<br />aged 46 |- | colspan=5 | Henry Bolingbroke seized the throne as Henry IV in 1399, and all of his titles merged with the crown.
| Henry of Monmouth<br />House of Lancaster<br />' | | 16 September 1386<br />Monmouth Castle<br />son of Henry IV and Mary de Bohun|| Catherine of Valois<br />2 June 1420<br />1 child | 31 August 1422<br />Château de Vincennes<br />aged 35 |- | colspan=5 | Henry of Monmouth succeeded to the throne as Henry V in 1413, and his titles merged with the crown.