Lancaster, House of the English royal house descended from John of Gaunt, Duke of Lancaster, that ruled England from 1399 ( Henry IV) until 1461 (the deposition of Henry VI) and again on Henry's brief restoration in 1470–1. With the red rose as its emblem it fought the Wars of the Roses with the House of York, both houses being branches of the Plantagenet line. Lancaster's descendants, the Tudors, eventually prevailed through Henry VII's accession to the throne in 1485.

The Duchy of Lancaster is now an estate vested in the Crown, consisting of properties in Lancashire and elsewhere in England.

Lancaster, House of English royal dynasty. The first Earl of Lancaster was Edmund ‘Crouchback’ (1245–96), son of Henry III. In 1361, the Lancastrian title and lands passed to John of Gaunt via his wife. In 1399, their son was crowned Henry IV. During the Wars of the Roses in the 15th century, the rival royal houses of Lancaster and York, both Plantagenets, contended for the throne.