Alain participated in the Conquest of 1066 and obtained from William the Conqueror, the Barony and castle of Oswaldestre (Oswestry), Shropshire, and Milcham, Norfolk, some of which belonged to Meredith, Prince of Powys ap Bleddyn, King of Powys. He received the shreivalty of Shropshire from King Henry I. While his parentage is more or less obscure, there is evidence to show that Flathald, his father, lived in Brittany and was a brother of Alain, seneschal of Dol, descended from the old Armonican Counts of Dol and Dinan.

Alain Fitz Flaald and Adeline were the parents of:

William Fitzalan

Alain and Adeline were benefactors to the Priory of Castle Acre, early in the reign of Henry 1