In lines 311-341 of Erec and Enide, Chrétien de Troyes names King Amauguin among Arthur’s allies and advisors.
Almost certainly, he is identical with the Amauguin found among Arthur’s knights in the list beginning in line 1691 of the same work.
He was defeated by Sir Gasozein of Dragoz while traveling in Arthur’s company.
Erec | Chrétien de Troyes, late 12th century
Diu Crône | Heinrich von dem Türlin, c. 1230