Two entries with the name Luce.
Luce
A giant whose brother, Menedron, was slain by Guiron the Courteous.
Luce imprisoned Guiron in his castle in Sorelois for seven years to avenge the death.
Source
Palamedes | c. 1240
Luce
A knight in the service of King Mark of Cornwall.
He led a battalion of Mark’s warriors against the invading Saxons, led by Helyas.
Source
Prose Tristan | 1230-1240