[...] In the old pagan times a Peistha, or water serpent, of immense girth and of still greater trail, was believed to haunt the celebrated Lough Derg, in the northern parts of Ireland. Sometimes his horrid head and open jaws were seen above the surface, as if drawing in the upper air. More frequently the fishermen saw him gliding slowly through the depths. When St. Patrick landed at Saints’ Island, that large water serpent was known to have tenanted the waters of Lough Derg. He had caused the destruction of many dwelling on the banks.

But the saint could not tolerate the presence of such a monster, and accordingly, with a stroke of his staff the Peistha was destroyed. Afterwards, the waters of the lough began to assume a reddish tinge, so freely did the monster bleed. To the present day has that colour continued—hence the name given to it: the Red Lake.

The skeleton remained on Station Island to the beginning of the present century, as the old people living around the shores are ready to asseverate; and many of them have conversed with persons who alleged they saw the last remaining portions of that serpent’s body mouldering into dust.