Inchcleraun

• 719 St Sionnach of Inchcleraun died on 20 April.
• 769 Curoi, the son of Alniadh, Abbot and Sage of Inchcleraun, and of Caill Fochladha (Lough Derravaragh) in Meath died.
• 780 Eochaidh, the son of Focartach, Abbot of Fochladha and of Inchcleraun, died.
• 1010 The men of Munster plundered Inchcleraun and Inis Bo-finne
• 1050 Inchcleraun was plundered
• 1087 The fleet of the men of Munster, with Muirchertach Ua Briain, sailed on the Shannon to Lough Ree and plundered the islands of the lake (inc. Inchcleraun)
• 1136 Áed Ua Finn (Hugh O'Flynn), the Bishop of Bréifne, died in Inchcleraun
• 1141 Giolla na Naomh Mac Fearghail, chief of the people of Annaly (Angaile), the most prosperous man in Ireland, died at a great age and was buried at Inchcleraun.
• 1150 Morogh, the son of the above, the tower of splendour and nobility in East Connacht died in Inchcleraun.
• 1160 Gilla na Naomh Ó Duinn, ollam of Inchcleraun, teacher of history and poetry sent his spirit to the Supreme Father amidst a choir of angels on the 17th day of December in the year of his 58th birthday.
• 1167 Cinaeth Ua Cethearnaigh, Priest of Inchcleraun died.
• 1168 Dubhcobhlach, the daughter of O'Quinn, wife of Mac Corgamna, died and was interred in Inchcleraun
• 1170 Diarmaid Ó Briain, Coarb of Comman, was chief senior of the east of Connaught, died in Inchcleraun in the 95th year of his age.
• 1174 Rory O'Carroll, Lord of Éile, was slain in the middle of Inchcleraun
• 1189 It was at Inchcleraun on Lough Ree that the hostages of O'Connor Maon-Moy were kept at the time.
• 1193 Inchcleraun was plundered by the sons of Costelloe and by the sons of O'Connor Maon-Moy
• 1232 Tiapraide O' Breen, Coarb of Saint Coman, an ecclesiastic learned in History and Law, died on his pilgrimage on the island of Inchcleraun
• 1244 Donnchad mac Fíngein Ó Conchobhair, who was the grandson of Hugh, son of Torlogh O'Connor, Bishop of Elphin, died 23 April on Inchcleraun, and was interred in the monastery of Boyle.

A monastery founded by Saint Diarmaid the Just in 540 AD is the most prominent ruin. Diarmaid was a teacher of Ciarán of Clonmacnoise.

This monastery is by far the most important ruin on the island. The church consists of a single nave 14.5 m (48 ft) long and 6.5 m (21 ft) wide. The walls are about 4 m (13 ft) high. There are two graceful lancet windows at the east end which are long, narrow and well recessed.

The windows on the south side have the appearance of later additions and are unsymmetrical. All traces of doors have vanished, but the opes, which have been arched and protected by the Board of Works, seem to indicate the position of a west door and an entrance on the north side to the cloister. An upper chamber exists and when perfect, covered the Chapter-house sacristy, and the east cloister, the internal walls of the lower apartments forming intermediate supports for the flooring. The interior walls of the church were once plastered.

John O'Donovan referred to this building as two churches: the monastic apartments as one and the vaulted sacristy as a penitential prison, labelling it "Deartheach".

The largest church. According to local lore, any woman who enters Templemurray will die within a year.

One of the churches, crowning the highest point of the island. has a square bell tower (Irish: clogas), which is attached to the main building, which is . Most churches of this era had round towers, separate from the main building. It is located on the northern part of the island and is visible from the shoreline. On the plan the church is rectangular, being 10.6 m (35 ft) by 5.1 m (17 ft).