Naming him among Arthur’s knights in the list beginning line 1691 of Erec and Enide, Chrétien de Troyes adds that the Count of Honolan had a fine head of fair hair, never had regard for truth, and recieved the horn of an ill-fated king (Arthur himself?) who appears to be unidentified in this passage save by the definite article.
Source
Erec | Chrétien de Troyes, late 12th century