I've been away for 2 weeks and am just catching up.
Ritual artificial lakes are found near Emain Macha (The Lake of the
Treasures), the Temple of Carnac at Luxor, and in the south of
Denmark, among other places. We don't know exactly how they were
used, but there is some evidence on which to base guesses: ritual
bathing, a depository for weapons captured from a defeated enemy, a
place to throw gifts to the gods. Nydam in Denmark held hundreds of
deliberately broken and bent swords and spears, as well as a boat
that had been dragged from a nearby river and cut up. The purpose
seems to have been to offer the weapons to the gods, as well as to
render the weapons useless to the enemy.
A curious modern echo of this is the Garden of Remembrance in Dublin,
dedicated to those who fought and died for Irish freedom. The pool
is cross-shaped, and the tiles under the water depict broken weapons.
Along with natural and artificial caves -- passage tombs are often
called "caves" locally -- bodies of water are often seen as entrances
to the Otherworld, and so it is natural for a holy person, Christian
or otherwise, to pray in water so as to be closer to the intended
recipient of the prayer.
Richard Marsh <[log in to unmask]>
Stories and Places of Irish Myth and Legend