Lugubelenus

Older form (possibly) of LLYWELYN.

LLYWELYN   male   Welsh
Possibly a Welsh form of the old Celtic name Lugubelenus, a combination of the names of the gods LUGUS and BELENUS. Alternatively it may be derived from Welsh llyw "leader". This was the name of several Welsh rulers, notably the 13th-century Llywelyn the Great who fought against England.
LUGUS   male   Celtic Mythology
Probably from early Celtic meaning "light", ultimately from the Indo-European root *leuk "light, brightness". This was the name of a Celtic (Gaulish) god of commerce and craftsmanship, who was equated by the Romans with Mercury. He probably forms the basis for the characters and names of Lugh (Irish) and Lleu (Welsh).
BELENUS   male   Celtic Mythology
Probably from a Celtic word meaning "bright, brilliant". This was the name of a Gaulish solar god who was often equated with Apollo.
OTHER FORMS
CELTIC MYTHOLOGY: Belenus, Lugus
WELSH: Leolin, Lewella, Llew, Llewella, Llewellyn, Llewelyn, Llywellyn, Llywelyn