Guillermo I de Escocia
William was pincerna (cup bearer or butler) to Malcolm IV and William the Lion, succeeding his uncle, Ranulf I de Soules, although the exact dates that he held this position are unknown. He witnessed some of the later charters of Malcolm IV, in one of which he is styled pincerna, and he is also styled as such in some of the early charters of William the Lion, and in a charter that he himself granted in 1171.