Patrick Denn was from Coolroe, near Mountain Ash, Co. Waterford. He was a proscribed hedge schoolmaster, as was his father, Laurence. He is recorded as living in Affane in 1800. We later discover him living in Cappoquin. He worked there as parish clerk and schoolmaster. His school was in the Main Street in Cappoquin. One of his many pupils was Dr. John Power, Bishop of Waterford. Denn also taught Christian Doctrine, in Irish, in the church on Sundays. He wrote and published a number of books to help him in this teaching. Drs. Power and Sheehan were great admirers of his writings and these writings were widely known throughout the county.

Among Denn's main works were 'Aigneas an Pheacaigleis an Mbas', 'Comhairle an Pheacaig agus aitheantha de Minighthe', and 'Stiurtatheoir an Pheacaig'. Denn died on 5 July 1828, aged 72 years. Dr. Power erected a small plaque on the wall of Cappoquin churchyard over his grave. It stated 'Of your charity pray for the repose of the soul of Patrick Denn, whose remains repose beneath this slab. The religious works written by him in the Irish language met with general approval and are proofs of his learning as an Irish scholar, and his zeal and piety as a sincere Christian.'