The Feudal barony of Trematon (or Honour of Trematon) was one of the three feudal baronies in Cornwall which existed during the mediaeval era. Its caput was at Trematon Castle, Cornwall. In 1166 it comprised 59 knight's fees, thus about 59 separate manors.
The barony of Trematon was unusual in that unlike most other English feudal baronies it was not held from the king in-chief but from the descendants of Robert, Count of Mortain, half-brother of King William the Conqueror. It was held for several generations by the de Vautort family (Latinized to de Valletorta, alias Valletort) which originated at the manor of Vautorte in Mayenne, north-western France. The descent of the barony was as follows:
Reginald I de Vautort (died post 1121), the first holder of the barony, was a major tenant of Robert, Count of Mortain (d.1090), half-brother of King William the Conqueror. He held the manor of Trematon from Robert.
Roger I de Vautort (floruit 1130-61)
Ralph I de Vautort (d.1172), who in 1166 according to the Cartae Baronum held 59 knight's fees from the Count of Mortain.
Reginald II de Vautort (d.1187)
Roger II de Vautort (d.1207)
Reginald III de Vautort (1196-1246), died without progeny.
Ralph II de Vautort (d.1256), brother and heir.
Reginald IV de Vautort (1236-1270)
Roger III de Vautort, uncle
Richard, 1st Earl of Cornwall (1209-1272), second son of King John and Isabella of Angoulême, bought the barony in 1270.
Edmund, 2nd Earl of Cornwall (1249-1300), son and heir, died without progeny when the barony escheated to the crown.
Piers Gaveston, 1st Earl of Cornwall (d.1312), was granted the barony in 1309, but following his execution in 1312 it reverted to the crown.
Queen Isabella, wife of King Edward II, granted the barony in 1317, which she retained during her husband's reign.
John of Eltham, Earl of Cornwall (1316-1336), second son of King Edward II and his queen Isabella of France, was granted the barony in 1331, and died without progeny.
Edward, the Black Prince (d.1376), eldest son of King Edward III, was granted the barony in 1337.
