The background of Herleva and the circumstances of William's birth are shrouded in mystery. The written evidence dates from a generation or two later, and is not entirely consistent, but of all the Norman chroniclers only the Tours chronicler asserts that William's parents were subsequently joined in marriage. The most commonly accepted version says that she was the daughter of a tanner named Fulbert from the town of Falaise, in Normandy. The meaning of filia pelletarii burgensis is somewhat uncertain, and Fulbert may instead have been a furrier, embalmer, apothecary, or a person who laid out corpses for burial.
Some argue that Herleva's father was not a tanner but rather a member of the burgher class. The idea is supported by the appearance of her brothers in a later document as attestors for an under-age William. Also, the Count of Flanders later accepted Herleva as a proper guardian for his own daughter. Both of these would be nearly impossible if Herleva's father was (and therefore her brothers were[citation needed]) a tanner, which would place his standing as little more than a peasant (wikipedia)