On Saints Island can been seen the ruins of an Augustinian Monastery that survived up to the time of the suppression of the monasteries in the reign of Henry the VIII. It flourished during the fourteenth century under the scholarly Abbot Augustin Magraidin, but the ravages of time took their toll and the site lay derelict for centuries. Augustin Magaidrin has been described as a sage during his lifetime in divine and worldly wisdom. He was the author of an important manuscript collection of the lives of Irish Saints which has been a valuable source for later writers. The work is now preserved in the Rawlinson collection of manuscripts in the Bodleian Library, Oxford. Magaidrin also compiled the Annals of the Abbey of All Saints, Lough Ree, listed by the Four Masters as one of their sources. This is also available in the Bodhleian Library. Magaidrin died in 1405. Saints Island has been linked to the mainland by a causeway for some years. This quiet water place is a favourite haunt of marsh birds. In spring the curlew, lapwing and various species of wild duck may be seen in great numbers. It is a picturesque and spiritual place to while away an hour or two in contemplation not only of nature but of Irelands ancient history as the Land of Saints and Scholars.
Saints' Island is one of the most important islands in Lough Ree, and was the site of a splendid monastery built by St. Kieran, the first Bishop of Clonmacnoise, in the year 544. After founding the monastery, he appointed as his abbot St. Domnan, and then left the island and repaired to Clonmacnoise, where he lived during the remainder of his life.No other mention is made of it until 1089, when, as well as the other islands in the neighbourhood, it was plundered and despoiled by Murkertach O'Brien and a large fleet of Danes and Ostmen. In 1272, the death of the Abbot Arectac Y. Fin is mentioned, so that the monastery must have been restored as well as its sister edifices on the neighbouring islands; and in the same year we find it mentioned that Sir Henry Dillon, of Drumrany, who had come into Ireland with the Earl of Morton, erected an abbey on the site of St. Kiernan's structure. There being no mention made of the destruction of the latter, it is difficult to understand how Sir Henry could have erected a monastery, unless he demolished the old one in order to substitute a better one, particularly as the death of the existing abbot is recorded in the same year. In the year 1405, the Canon Augustine M'Graidan died, and was interred in the chancel of his chapel. He was a very learned man, and is said to have written the lives of all the Irish saints, as well as the records of the abbey, down to his own time, both of which works are yet preserved in the library of Oxford. James I. of England granted this island, as well as portion of the islands and land in the lough, to Sir Patrick Barnewall, in the year 1620, but it was again taken from him for his part in connexion with the petition of Catholic grievances in the following reign. In a small island near Lanesborough called Inch Ainghin, St. Kieran also built a church. "894. Inch Ainghin was violated, and persons were wounded in the middle of it, although St. Kieran's shrine and many religious persons, together with Cairbree Cronn, Bishop of Clonmacnoise, were present. "895.Toictuch, of Inch Yana, died. "1015, 1050, and 1089. This island shared the same fate as the other islands in Lough Ree."