St. Patrick visited Donaghmore in the 5th century and established a church. The Tripartite Life of St Patrick records that he set up seven Episcopal churches in the area around Slieve Gallion and Lough Neagh.
St Patrick converted the local people at Donaghmore – the Fír Imchlair. He baptised them as Christians in the Torrent River. The Church became known as Maigh Imchair. St Patrick left a priest named Colum Cruither in charge, and entrusted his book and bell. The bell became known as “The Bell of Clogher” and still survives today in the National Museum, Dublin.
The location of the monastery was possibly on an earlier pagan sacred site as there is much evidence of earlier settlers dating back many centuries in the area.
The name “Donaghmore” in Irish is “Domhnach Mór” which is sometimes taken to mean “Big Church”. But it has also been suggested that it means “Big Sunday” referring to the gathering of people coming to worship at the site each week – and before there was a specific word to describe that worship.
The Church at Donaghmore developed into a monastic foundation, in a similar way to monasteries throughout Ireland at the time. These monasteries were pivotal to education and knowledge in Ireland and would have attracted scholars from throughout the Island and Western Europe up until the 11th and 12th Centuries.
Donaghmore Monastery was influential and Dermot O’Tierney of the Fir Imchlair undertook the prestigious position of Abbot of Armagh circa AD 834.
In the taxation survey of AD 1291 conducted by Pope Nicholas IV it is described as being wealthy and influential with many costly shrines and up to 1300 acres of land. The High Cross in Donaghmore dates to the 10th Century (see separate section for more detail) and was likely to be one of three such crosses on the site.
As the monastic system came to an end in Ireland, the monastic sites lost influence. So by early 1600 maps show no sign of the monastery in Donaghmore, as it was possibly completely destroyed by Jacobean forces during the era of destruction that came after the Flight of the Earls in 1607.