ntinental Celts that far off there was a divine land where the sun-god
rested. When the Celts reached the coast this divine western land would
necessarily be located in a far-off island, seen perhaps on the horizon.
Hence it would also be regarded as connected with the sea-god, Manannan,
or by whatsoever name he was called. The distant Elysium, whether on
land or across the sea, was conceived in identical terms, and hence also
whenever the hollow hills or _sid_ were regarded as an abode of the
gods, they also were described just as Elysium was.

The idea of a world under the waters is common to many mythologies, and,
generally speaking, it originated in the animistic belief that every
part of nature has its indwelling spirits. Hence the spirits or gods of
the waters were thought of as dwelling below the waters. Tales of
supernatural beings appearing out of the waters, the custom of throwing
offerings therein, the belief that human beings were carried below the
surface or could live in the region beneath the waves, are all connected
with this animistic idea. Among the Celts this water-world assumed many
aspects of Elysium, and it has names in common with it, e.g. it is
called Mag Mell. Hence in many popular tales it is hardly differentiated
from the island Elysium; oversea and under-waves are often synonymous.
Hence, too, the belief that such water-worlds as I-Bresail, or Welsh
fairy-lands, or sunken cities off the Breton coast, rise periodically to
the surface, and would remain there permanently, like an island Elysium,
if some mortal would fulfil certain conditions.[1256]

The Celtic belief in Tir fa Tonn is closely connected with the current
belief in submerged towns or lands, found in greatest detail on the
Breton coast. Here there are many such legends, but most prominent are
those which tell how the town of Is was submerged because of the
wickedness of its people, or of Dahut, its king's daughter, who
sometimes still seeks the love of mortals. It is occasionally seen below
the waves or even on their surface.[1257] Elsewhere in Celtic regions
similar legends are found, and the submersion is the result of a curse,
of the breaking of a tabu, or of neglect to cover a sacred well.[1258]
Probably the tradition of actual cataclysms or inroads of the sea, such
as the Celts encountered on the coasts of Holland, may account for some
of these legends, which then mingled with myths of the divine
water-world.

The idea that E