DMLBS has two entries for what is perhaps the same word, each with only one supporting citation: for gerulfus, Gervase of Tilbury’s definition from 1215: ‘vidimus enim frequenter in Anglia per lunationes homines in lupos mutari, quod hominum genus gerulfos (var.: verulos) Galli nominant, Anglici vero werewulf dicunt. were enim Anglice virum sonat, wlf lupum’ (Otia Imperialia I,15); and for werwolfus, the late (1480-1490) Digby Plays line: ‘fartum cardiculorum … snyguer snagoer werwolfforum’. Gerulfus is important for Romance philologists (cf. DEAF G334 garol [Möhren]; FEW 17,571a) because it confirms the possibly corrupt readings in Marie de France. Both FEW and TL reconstruct a form [garulf], which is plausible but of course unattested. The main point though is that both Marie and Gervase confirm that the form gerulfus/*garulf is French (specifically Norman in Marie’s case). Werwolfus with initial w- is explicitly English.