Dylan
Boy
Dylan’s sea connection begins with a story. In the Fourth Branch of the Mabinogi, Dylan is Arianrhod’s son, who enters the sea soon after birth.
This is an episode of legend, not history.
One proposed reading of Dylan. One proposed reading joins Welsh dy, “to” or “toward”, with llanw, “tide” or “flow”.
The sea story is a literary association; this etymological proposal is not a settled translation.