A Book of Myths, by Jean Lang - Umnet

Then said her brothers: "In Him we put our trust," and from that
moment the Lord of Heaven gave them His help, so that no frost, nor
snow, nor cold, nor tempest, nor any of the creatures of the deep could
work them any harm.
When the nine hundred years of their sorrowful doom had ended, the
children of Lîr joyously spread their wings and flew to their father's
home at Shee Finnaha.
But the house was there no more, for Lîr, their father, was dead. Only
stones, round which grew rank grass and nettles, and where no human
creature had his habitation, marked the place for which they had longed
with an aching, hungry longing, through all their weary years of doom.
Their cries were piteous as the cries of lost children as they looked on
the desolate ruins, but all night they stayed there, and their songs were
songs that might have made the very stones shed tears.
Next day they winged their way back to Inis Glora, and there the
sweetness of their singing drew so many birds to listen that the little
lake got the name of the Lake of the Bird-Flocks. Near and far, for long
thereafter, flew the swans, all along the coast of the Western Sea, and at
the island of Iniskea they held converse with the lonely crane that has
lived there since the beginning of the world, and which will live there
until time is no more.
And while the years went by, there came to Erin one who brought glad
tidings, for the holy Patrick came to lead men out of darkness into light.
With him came Kemoc, and Kemoc made his home on Inis Glora.
At dawn one morning, the four swans were roused by the tinkle of a
little bell. It was so far away that it rang faintly, but it was like no
sound they had ever known, and the three brothers were filled with fear
and flew hither and thither, trying to discover from whence the strange
sound came. But when they returned to Finola, they found her floating
at peace on the water.
"Dost not know what sound it is?" she asked, divining their thoughts.