Amurfina
Daughter of Lord Laniure of Serre and Ansgien, sister of Sgoidamur, and eventual wife of Gawain in Heinrich’s Diu Crône.
When her father died, Amurfina took possession of a magic bridle that controlled the family fortune, thus disinheriting her sister. In the dispute, both of them solicited Gawain as their champion.
While Gawain was visiting her castle, her servant Aclamet served him a love potion which caused him to fall madly in love with Amurfina. They married and Gawain became the lord of Serre. Amurfina’s uncle, Gansguoter, was Arthur’s step-father.
A character of similar nature appears unnamed in La Mule sans Frein.
Source
Diu Crône | Heinrich von dem Türlin, c. 1230