*William (Robert) de Ferrers, 4th Earl of Derby
born 1144 Derby, Derbyshire, England
died after 31 December 1189 Seige of Acre, Jerusalem, Palestine
buried before 21 October 1190 Normandy, France

*William de Ferrers, 3rd Earl of Derby
born abt 1120 Of Derbyshire, England
died 1240

*Margaret Peverel
born Abt 1114 Of, Nottingham, Nottinghamshire, England
married Abt 1135 Of, Nottinghamshire, England

Wacheline De Ferreres

*Sibilla Braose
born about 1157 Bramber, Sussex, England
died after 05 February 1227/28 England
married about 1173/74? Sussex, England

*William de Ferrers born about 1175? Ferrers, Derbyshire, England died 22 September 1247
*Millicent de Ferrers born about 1170? Derby, Derbyshire, England
*Petronilla de Ferrers born before 1189 Derbyshire, England
*Agatha de Ferrers born about 1170? Charltey, Staffordshire, England

biographical and/or anecdotal:
Robert de Ferrers, 4th Earl of Derby, rebelled against Henry II., and marching at the head of the Leicester men (in the 19th year of Henry II.), upon Nottingham, then kept for the king by Reginald de Luci, got possession of the town, which he sacked, putting the greater part of the inhabitants to the sword, and taking the rest prisoners. He was soon afterwards, however, reduced to submission, and obliged to surrender to the crown his castles of Tutbury and Duffield, which were demolished by order of the king.

There is substantial confusion over his name.
See The Complete Peerage V4.p193 for an account.
notes or source:
LDS & Homer Beers James