[6] Under King John (1199–1216) Brewer was one of the most active figures in government, in terms of the number of royal charters he witnessed,[7] together with Henry Marshal, Bishop of Exeter and Geoffrey FitzPeter, 1st Earl of Essex.
[9] In 1224, he retired from the world to live as a Cistercian monk at Dunkeswell Abbey, where he died in 1226 and was buried with his wife before the high altar.
Their children included: Brewer was adept at acquiring lands, and obtained a substantial feudal barony from relatively humble beginnings.
[20] Risdon stated that Brewer held close to thirty knight's fees (usually synonymous with manors) in Devon, and that his barony ("honour") was "incorporated to the crown" together with the Dukedom of Lancaster, by King Henry IV.
[18] His Devonshire landholdings included: William Brewer is a possible original for the Sheriff of Nottingham in the Robin Hood legends.