Duke William- jewish ancestry?

Was William’s mother, Herleve, jewish?

In 1051 Duke William invaded the wild and hilly region of Belleme (strategically placed and contested by French Kings, Normandy AND Anjou) aiming to block Angevin expansion & capture the two key frontier forts of Domfront and Alencon, that Geoffrey of Anjou had garrisoned with troops, and that William feared would be used as a springboard to invade Normandy further. But Geoffrey retreated before the Duke's army.

However,according to William of Jumieges, at Alencon, the spirited defenders taunted the besieging Duke by hanging hides over the town's walls and shouting "Hides for the tanner" - a derogatory reference to his tanner mother's profession and lowly birth, and also his own bastardy.

Wace's account might give a clue as to the original French of the joke which the Duke found so offensive.
The French for skin, according to Wace, is "la pel". In the masculin "le pel" the word means stake, pallisade, or wall. Bearing in mind, it is conceivable that the defenders of Alençon were making a pun by shouting "the walls, the walls" to the Duke [the pelterer]. But more probably, the pelts or skins did not refer to animals, but to human corpses.

"Pellis" in Latin, and "la pel" in old French, can both indicate animal as well as human skin. Could the mockery have been insulting because Duke William's grandfather had been a pollinctor in the only known sense of the word, that is, a person who prepares corpses for burial, an undertaker or even an embalmer.
As such, the father of Herleva naturally would have dealt with skins, not however with those of animals, but of human beings.

The people of Alençon could not possibly have referred to this profession by beating human corpses or skins, so they therefore used pelts. In French, they shouted 'Pelterer' and Orderic translated this as pelliciarius, thereby preserving the double meaning.
He still knew the nature of the insults and the real occupation of Herleva's father; whereas, half a century later, neither Wace nor Benoit seem to have been aware of the real facts.

Were these hides simply hung over walls as defence against fire -as was common practice then "or was William’s mother, Herleve, jewish? Almost exclusively tanners were jews at this time, so was it an anti-semitic taunt?

When the town was finally captured, William singled out those responsible, blinded them and had their hands & feet cut off, then threw them over the high walls.

As William returned to Domfront, it immediately surrendered, having heard of the earlier atrocities at Alencon, but William couldn't capitalise on these successes with his available forces, and withdrew.