Keu
Caer Gai, a Roman fort near Llanuwchllyn, was traditionally known as the home of Cei, the character in the Arthurian legend known in English as Sir Kay. Poets of the 15th century recorded a story, ultimately deriving from the Prose "Merlin" included in the Lancelot-Grail and the Post-Vulgate Cycle, that King Arthur and Cei were brought up at Caer Gai as foster brothers. Caer Gai is also Grade II* listed.