Arnaut Guilhem was the ancestor of three branches of the house of Marsan through his three sons: the co-lords of Marsans and lords of Roquefort and Montgaillard; the lords of Cauna; and the lords of Tardets.
Having negotiated the tricky issue of translating into a language which by then had no great written tradition, common standard or spelling system, he persevered with some help from four old Catholic colleagues: Piarres Landetxeberri from Espès-Undurein, Sanz de Tartas from Charritte-de-Bas (both in Soule), Joanes Etxeberri from Saint-Jean-de-Luz and a Mr Tardets who was a minister in Ostabat.