Lancaster

English royal house, a branch of the Plantagenets.

It originated in 1267 when Edmund (died 1296), the younger son of Henry III, was granted the earldom of Lancaster. Converted to a duchy for Henry of Grosmont (died 1361), it passed to John of Gaunt in 1362 by his marriage to Blanche, Henry's daughter. John's son, Henry IV, established the royal dynasty of Lancaster in 1399, and he was followed by two more Lancastrian kings, Henry V and Henry VI.