Ninnidh

Saint Ninnidh, also called Nennius or Ninnidh the Pious, was an Irish monk of the sixth century, a disciple of Saint Finian of Clonard and reckoned among the Twelve Apostles of Ireland.

He was born in County Donegal, a grandson of the high king Laoghaire. He studied at Clonard, where his fellow students included Saints Ciaran of Clonmacnoise, Molaise of Devenish and Aidan of Ferns. He preached along the southern shore of Lough Erne, making the island of Inishmacsaint his headquarters around 532, where he built a monastery. It is said that he used the waters of the lake to reach the people, sending priests and monks to the local churches, and that during Lent he kept a forty-⁠day fast on Knockninny Hill. Accounts of his life have largely been lost.

His well at Knockninny, on the shore of Lough Erne, was held to cure eye ailments. He is a saint of the undivided Church, commemorated on 17 January (new style); other sources give 18 January.