NIGHTBRINGER | The Arthurian Encyclopedia

Juan of Castille


In Spanish romance, the king of Castile whom Tristan the YoungerTristan’s son, eventually served.

Tristan the Younger married Infanta Maria, Juan’s daughter, after rescuing her from the Moors. Juan married Iseo (Isolde), Tristan the Younger’s sister.


Source
I Due Tristani | 1555