Fenagh Abbey, as it is known, is in fact a 15th century church built on the site of an earlier Christian monastery. The original ecclesiastical site was founded by St Caillín in the 6th century, the Annals of the Four Masters states that Fenagh was, “celebrated for its divinity school, which was resorted to by students from every part of Europe”. Fenagh must have been a pivotal site in early Christian Ireland, the Book of Fenagh which was completed in the monastery in 1516 detailed the life of St Caillín, parts of which were transcribed from the earlier, now lost, ‘Old Book of St Caillín’.

Much legend is attached to the area, a number of standing stones in the surrounding countryside were said to represent the petrified bodies of druids who tried to expel St Caillín. Nineteen Gaelic kings are also said to be buried in the graveyard. The church was dissolved in 1541 but it appears that it was re-occupied at some later date until 1652 when it was sacked by Cromwellian soldiers. The church was damaged by cannon fire during the Williamite wars in 1690. The church was used by the Anglican community during the 18th century, the last service was said in 1729.
The importance of this are is reflected in its prominence in early Irish literature, Magnus, son of Muirchertach Muimnech (from the Annals of Connacht), wrote in 1244:

“Fedlimid mac Cathail Chrobdeirg made an immense hosting eastwards into Brefne against O Raigillig, to avenge his fosterson and kinsman, Tadc O Conchobair. They encamped for a night at Fenagh. At that time there was no roof on the church of Fenagh, and the coarb was away that night. And as he was not present, the common soldiers of the host burned the huts and tents which were inside the church, without permission of their leaders, and the coarb’s foster-child, God’s gift, was suffocated. Now learned men relate that the coarb received this foster-child by finding him on a large stone which stood in that place, and [the people] never knew of his having either mother or father; and the coarb loved him and gave him, as it is said, milk from his own breasts. Next day he came to them in anger and indignation at the death of the boy, requiring O Conchobair to pay the blood-fine for his foster-child, and O Conchobair said he could choose what fine he pleased. ‘I choose’ said he ‘the best man among you, as compensation for the child of God whom you have burnt.’ ‘That’ said O Conchobair ‘is Magnus, the son of Muirchertach Muimnech.’ ‘Nay, not so,’ said Magnus ‘but he who is leader of the host.’ ‘I will not go from you so’ said the coarb ‘until I get the fine for my foster-child.’ After this the host departed from that place, and the coarb followed them to Ath na Cuirre on the Yellow River, which was flowing over its banks, so that they could not cross it till they broke up the spital-house of John the Baptist, which stood beside the ford, and used its materials to bridge the river for the host to pass across. Magnus son of Muirchertach Muimnech and Conchobar son of Cormac Mac Diarmata went into the house, and Magnus spoke to a man who was above him, at work on the house-breaking; ‘That’ said he, pointing upwards with the chape of his sword, ‘is the nail which keeps the house from falling.’ As he spoke, a rafter fell on his head and smashed it to pieces on the spot. He was buried outside the doorway of the church of Fenagh, and thrice the capacity of the Bell of the Kings of silver and thirty horses were given as an offering with him. Thus, then, did the coarb of St. Caillin at last recover compensation for his fosterling of God from them. A beautiful monument of carved stone with an excellently wrought stone cross was afterwards made [and set up] over him, but after a while the Ui Ruairc in their enmity demolished it.”

GPS: 54.01799, -7.83508