Amistant, Amistiax, Amnistan, Amustan, Amustant
The chaplain of King Leodegan of Carmelide (Leodegrance) (Guinevere’s father) in the Vulgate romances. He married Arthur and Guinevere and accompanied them to Arthur’s court, where he continued his service as chaplain. He later became a hermit, but he helped Arthur during the False Guinevere episode by identifying the real Guinevere.
Since he knew Guinevere in her childhood and was instrumental, by scolding Arthur and helping get deathbed confessions from Genievre and Bertholai, in reconciling Arthur with Guenevere after Genievre’s last attempt to supplant her half-sister.
In Lancelot of the Laik he is called Amytans.
Source
Vulgate Lancelot | 1215-1230
Vulgate Merlin | 1220-1235