Heroine of Chrétien de Troyes’s Cliges, endowed with a number of characteristics of Isolde, though Fenice explicitly wishes to avoid Isolde’s fate. She was the golden-haired and, of course, incredibly beautiful daughter of the Emperor of Germany, Fenice was courted by the Duke of Saxony, but her father agreed to marry her to Alis, the Emperor of Greece and Constantinople.
When Alis came to meet her in Cologne, Fenice fell in love with Alis’s nephew, Cligés, who had won fame at Arthur’s court.
To preserve her virginity, she had her servant Thessala create a potion to give to Alis. The potion caused Alis to believe that, each night, he was making love to Fenice when in fact he was only dreaming, with his bride still virginal at his side.
Fenice and Cligés eventually confessed their love for each other and developed a plan: Fenice would fake her own death, and Cligés would retrieve her from her tomb after burial. While Cligés had a special tomb made for the occasion, Thessala concocted another potion which would give Fenice the appearance of death. The potion worked, but three physicians arrived from Salerno who doubted Fenice’s death. They tortured the poor maiden with fire and whips to rouse her, until they were hurled out a high window by a force of Fenice’s lady servants.
Fenice was buried as planned, and Cligés rescued her. The wounds she had received from the physicians were mended by Thessala. Cligés and Fenice lived together in a tower for some time in bliss, but they were eventually discovered by Alis’s warrior Bertrand of Thrace. Cligés and Fenice were forced to flee Greece to escape Alis’s wrath. They would have enlisted Arthur, who was a great-uncle of Cligés, to help him win the throne of Greece and Constantinople; but Alis considerately died in time to let Cligés and Fenice come back peacefully to reign as emperor and empress. Cligés always trusted his wife, but Chrétien adds that no later emperor of Greece and Constantinople, remembering Fenice, ever trusted his.
Chrétien tells us Fenice’s as soon as she appears, adding that she was a matchless in beauty as her namesake the Phoenix bird.
Source
Cligés | Chrétien de Troyes, late 12th century