Distant about five miles due south from Longford, is the Cemetery of Abbey Dearg, in which stands the crumbling ruins of what was once a priory for Regular Canons of the Order of St. Augustine. This priory was founded about the year 1205, by Grormgall O'Quinn, Lord of Rathcline, and was dedicated to St. Peter; and in 1217, the first abbot of the monastery, Osin by name, died and was interred here. On the death of Brendan Jifagodaig, Bishop of Ardagh, in 1255, his remains also were interred in this priory, which continued to exist until 1550, when it was suppressed, and the buildings and land, to the value of £2 annually, Irish money, were bestowed on one Nicholas Alymor, an English soldier. The existing ruins of, the Abbey of Dearg prove it to have been a most perfect monastic structure. The plate which is not a very perfect one, owing to the entire demolition of the main walls of the building, and the complete covering of the walls, showing the eastern and southern window by a thick coat of impenetrable ivy. The ruins have been examined minutely, and the conclusion is that it consisted of a main chancel (of chapel), vestry, dining-room, dormitory, and a number of cells. The principal walls of all, except the southern and eastern portion of the chancel, are now demolished to a height of two or three feet.
More about Monastic Sites in Ireland you will find HERE.
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