Folio 309r of the Book of Kells (Trinity College Dublin), c. 800.
Key myth
He takes mortals across the sea to the otherworld in the Voyage of Bran. He is a trickster and a magician, and the Isle of Man is named for him in tradition.
Deities in other traditions who share a theme with Manannán mac Lir: sea and waters, trickery, boundaries and travel. This is overlap in one area only.