Gwendoloena (Gwendoleu)

Wife of Merlin (Merlinus or Myrddin).

In Vita Merlini, Geoffrey of Monmouth wrote that when Merlin went mad during the Battle of Arfderydd and fled into the forest, Gwendoloena stayed with her sister-in-law Ganieda (Gwenddydd) in the court of King Rodarch (Rhydderch Hael). She was reunited with Merlin when Rodarch's men caught him in the forest of Calidon.

When Merlin left Rodarch's court, Merlin gave permission for her to marry, but warned Gwendoloena that her future bridegroom must not see him when he came to give her a wedding present. This was sort of like the Irish geis (gesa), which is a prohibition or taboo.

On the day of her wedding, Merlin arrived at Rodarch's palace mounted on a stag, leading other deer. Gwendoloena, who was standing at the window, saw and laughed the spectacle of her ex-husband. Either she forgot to warn her new husband-to-be or he ignored her warning.

In any case, the bridegroom mocked Merlin. When the bridegroom stood before Merlin, Merlin ripped off the horn of the stag and flung it at Gwendoloena's lover, killing him. Merlin then returned to the forest. After this incident, we never heard from Gwendoloena again.

Apart from this event, Gwendoloena's role is small; Merlin's sister played a more important role in the prophet/enchanter's life. In fact, Gwendoloena doesn't even appear in the Welsh poems attributed to Myrddin, so the Vita Merlini is the only work that mentioned Merlin having a wife.