Two entries with the name Isolde.
Isolde
God-daughter of Tristan.
She was the daughter of Genes, the seafarer who brought Isolde of Cornwall to the mortally wounded Tristan’s bedside. Isolde told Isolde of the White Hands that Isolde of Cornwall was coming, which sparked the jealousy that led to Tristan’s premature death.
Source
Prose Tristan | 1230-1240
Isolde
The daughter of Tristan and Isolde in the Italian I Due Tristani.
She was born along with Tristan the Younger during Tristan and Isolde’s sojourn at the Castle of Tears. Raised by foster-parents, she grew into a beauty. Palamedes, who had loved her mother, tried to abduct her and was slain by Palante, Tristan’s cousin, in the process.
She later married King Juan of Castille, whom her brother served.
Source
I Due Tristani | 1555
Note
Variant of Iseult used in the thirteenth century by Gottfried von Strassburg, and in the nineteenth century by Richard Wagner.
See also
Isolde of Cornwall | The Legend of King Arthur