Daughter of King Guingras, from whom she inherited the kingdom of Wales.
The sorcerers Mabon and Evrain entered her kingdom, laid waste to her city of Snowdon (thereafter called Desolate City), and turned her into a serpent until either she agreed to marry Mabon or a knight rescued her by defeating the sorcerers and enduring a kiss from her in serpentine form – called the Fearsome Kiss.
Esmeree’s servant, Helie, traveled to Arthur’s court to find a knight to rescue her, and Helie came back with Gawaine’s son, Guinglain. Guinglain defeated the two wizards and reluctantly allowed the snake to kiss him, thus ending the curse. Esmeree wanted to marry Guinglain, but Guinglain, having fallen in love with the Maiden with the White Hands during the journey, made an excuse to leave, promising to rendezvous with Esmeree at Arthur’s court. When she reached Arthur’s court and failed to find Guinglain, Arthur – who approved of the marriage – called a tournament at the Castle of Maidens, knowing that Guinglain, who never missed a chance to win honor, would show.
Guinglain’s participation made him lose the love of the Maiden with the White Hands, and he was thus free to marry Esmeree. The two were wed in Wales, and Guinglain became King of Wales.
Source
Le Bel Inconnu | Renaut de Bâgé, 1185–1190