The English Augustinian Province was suppressed by King Henry VIII. He forced the closure of the last remaining Augustinian community in England at Hull on 10th March 1539. At that time, twenty Augustinian communities in Ireland also belonged to the Augustinian Province of England. Although officially suppressed as well, as many as ten that were beyond the effective reach of the forces of the king continued, at least for a while.

One of these was the Augustinian Priory (convento) at Dunmore, County Galway. It had been founded through the generosity of Walter de Birmingham, ninth Baron of Athenry, in 1423. By a letter dated 8th January 1430 Pope Martin V assisted the project by offering indulgences to contributors to the church and priory at Dunmore. It was occupied by as many as thirty members of the Order of Saint Augustine simultaneously, up to 30 friars until the Dissolution, in 1641.

After existing for almost 120 years, the Augustinian convento at Dunmore was preserved from closure in a unique manner – by the protection of the British Parliament. By a decree of 7th July 1542 the Parliament permitted that the priory at Dunmore continue.

This was because Lord Birmingham, a descendant of the founder of that community, requested its preservation. At the time of the suppression of the religious houses by Henry VIII Lord Bermingham interceded for this house, stating that it was founded by his ancestors, that it was a 'poor monastery' 'amongst the Irishrie', without profit or lands but 'only the small devotion of the people', and that its suppression would be of no gain to the king. The request was  granted by the Lord Deputy and Council on 7 July 1542, the prior and four friars were allowed to remain in occupation 

By the year 1610, all other Augustinian houses in Ireland had been forced to close, leaving only Dunmore operating. For that reason Dunmore priory became the mother house when the Augustinian Province of Ireland that was established in 1620. The Province was set up largely to give official structure and encouragement to the individual members of the Order of Saint Augustine who were risking their personal safety by struggling for the survival of the Order in Ireland. A Protestant remonstrance of June 1641 stated that at Dunmore was a fully organized monastery with a prior and some thirty friars who did not fear to appear publicly in their Augustinian habits 

As a result of this complaint, the official protection of Dunmore Priory lapsed, and it was dissolved later during that same year, having survived for 216 years. The Priory (convento) was demolished, and its chapel was used as a Protestant Church until relatively recently. This church is all that is left of the previously much larger monastery. It is still to be seen today, locked and without a roof, adjacent to a supermarket car park. The building has been modified over the years, e.g., arches have been filled in, and one side of the building was plastered in more recent years. Today the site is a national monument.

Links

The Augustinian Friaries in Pre-Reformation Ireland. The full text of 384 pages. A reference source of considerable value. Dunmore is mentioned briefly. 
https://archive.org/stream/TheAugustianFriariesInPre-reformationIreland/TheAugustianFriariesInPre-reformationIreland_djvu.txt

Dunmore Priory Ruins. Images.
https://commons.wikimedia.org/wiki/Category:Dunmore_Priory

Other ancient Augustinian monasteries in Ireland

Fetherd. Photographs and historical details of Holy Trinity Augustinian Priory, 
http://irishantiquities.bravehost.com/tipperary/fethard/fethardpriory.html  

Former Callan Priory building. Numerous good pictures of this ruin. 
http://irishantiquities.bravehost.com/kilkenny/callan/callan_priory.html 

Further reading

The Irish Augustinian Friaries in pre-Reformation Ireland. By F. X. Martin O.S.A. Augustiniana (6), April 1956: Augustinian Historical Institute of Louvain. pp 346-384.

AN4224