William FItzalan born between 1105 and 1110 in Oswestry, Shropshire.

In the contest between Stephen and Maud, being then Governor of Shrewsbury and Sheriff of the county of Shropshire, held the castle at Shrewsbury for the latter, until it was taken by assault. He was also with the Empress at the siege of Winchester Castle, in the 6th year of Stephen, when she and her whole army were put to flight; afterwards, continuing to adhere stoutly to the same cause, he was reconstituted Sheriff of Salop, when King Henry attained the crown. In the 12th year of Henry II, upon the assessment, in aid of marrying the King's daughter, certified his knight's fees to be in number thirty-five and a half.

He Married firstly Christian Fitzribert c.1135 and they had a daughter:

Christian Fitzalan

He secondly married Helen Peverell  born c. 1115.  Helen's father was William (Younger) Perevel and her mother was Avice de Lancaster.  Her paternal grandparents were William (Elder) Peverel and Adeline (Adeliza); her maternal grandparents were  Roger (Poitevin) II Montgomery and  Almodis (Audmodis) de la Marche.  She was the youngest of two children.  She had a sister named Margaret.  She had a half-brother named Richard.

William and Helen had a son:

William Fitzalan (Sheriff of Shropshire)

William died c.1172