Two 10th century Counts of Ponthieu had the P-Celtic (identical to Brythonic) names Haelchod and Herluin.

Charter 24 in the Cartulary of the Abbey of Landevennec records Count Haelchod and his son Herleuuin as witnesses of donations on 10 April and 13 August 954.

The abbots of Landevennec had fled Lower Brittany and crossed all the way to Montreuil-sur-Mer where Count Haelchod sheltered them. While in Ponthieu, they built a shrine to Saint Winwaloe (Guénolé in French).