WILLIAM DE FERRERS, buried 31 Mar 1254, 5th earl of Derby; married (1) by 14 May 1219, Sibyl, 3rd daughter of William Marshall (177-8), Earl of Pembroke, by isabel de Clare (66-27), d.s.p.m.; married (2) ca. 1238 Margaret de Quincy (57-29), died shortly before 12 Mar 1280/1. (Generations 28-30: CP IV 192-198, chart p. 199, V 320 chart, VII 677: SP III 142).55

There is substantial confusion over his name. See “The Complete Peerage,” V 4, p. 193, for an account. Personally, I feel there could have been two brothers, William and Robert. Robert being the Earl and when he died at Acre his nephew William, son of his brother William, succeeded, but no documents support this theory either.

Earl of Ferrieres