the birth-stories he is clearly Lug's son by Dechtire. But both
versions may simply be different aspects of one belief, namely, that a
god could be reborn as a mortal and yet continue his divine existence,
because all birth is a kind of rebirth. The men of Ulster sought a wife
for Cuchulainn, "knowing that his rebirth would be of himself," i.e. his
son would be himself even while he continued to exist as his father.
Examples of such a belief occur elsewhere, e.g. in the _Laws_ of Manu,
where the husband is said to be reborn of his wife, and in ancient
Egypt, where the gods were called "self-begotten," because each was
father to the son who was his true image or himself. Likeness implied
identity, in primitive belief. Thus the belief in mortal descent from
the gods among the Celts may have involved the theory of a divine
avatar. The god became father of a mortal by a woman, and part of
himself passed over to the child, who was thus the god himself.

Conchobar was also a rebirth of a god, but he was named from the river
whence his mother had drawn water containing the worms which she
swallowed. This may point to a lost version in which he was the son of a
river-god by Nessa. This was quite in accordance with Celtic belief, as
is shown by such names as Dubrogenos, from _dubron_, "water," and
_genos_, "born of"; Divogenos, Divogena, "son or daughter of a god,"
possibly a river-god, since _deivos_ is a frequent river name; and
Rhenogenus, "son of the Rhine."[1210] The persons who first bore these
names were believed to have been begotten by divinities. Mongan's
descent from Manannan, god of the sea, is made perfectly clear, and the
Welsh name Morgen = _Morigenos_, "son of the sea," probably points to a
similar tale now lost. Other Celtic names are frequently pregnant with
meaning, and tell of a once-existing rich mythology of divine _amours_
with mortals. They show descent from deities--Camulogenus (son of
Camulos), Esugenos (son of Esus), Boduogenus (son of Bodva); or from
tree-spirits--Dergen (son of the oak), Vernogenus (son of the alder); or
from divine animals--Arthgen (son of the bear), Urogenus (son of the
urus).[1211] What was once an epithet describing divine filiation became
later a personal name. So in Greece names like Apollogenes, Diogenes,
and Hermogenes, had once been epithets of heroes born of Apollo, Zeus,
and Hermes.

Thus it was a vital Celtic belief that divinities might unite with
mortals and beget chil