This monastery is situated on the banks of the Shannon, it was founded in 544 AD by St Ciarán on a fertile meadow, or cluain, surrounded by bog. It could be reached only by river or along esker ridge known as the pilgrim’s road. The monastery flourished for 600 years as a centre of learning and religious instruction. It also supplied much of Ireland’s finest Celtic art and illuminated manuscripts (i.e., the beautiful Clonmacnoise Crozier, considered to be one of the finest ecclesial items to have survived, on view at the National Museum, Dublin; the finely decorated metalwork shrine of the Stowe Missal was also made at Clonmacnoise). The earliest known manuscript in the Irish language Lebor na hUidre (The Book of the Dun Cow so-called after a cow that belonged to St Ciarán) was written at Clonmacnoise in the 12th century.

After the monastery of Clonmacnoise was broken up, the manuscript came into the possession of the O’Donnell clan of Donegal who held it until 1359, when it and the lost Leabhar Gearr were used to ransom members of the clan who had been taken prisoner by Cathal Óg O’Connor. Áed Ruad O’Donnell recovered the manuscript in 1470, and it remained in Donegal at least until 1631, when the compilation of the Annals of the Four Masters was completed. Its location was unknown until 1837, when it was part of a collection owned by Messrs. Hodges and Smith of College Green, Dublin, and was cited by George Petrie in an essay on the History and Antiquities of Tara Hill. The Hodges and Smith collection, 227 manuscripts in all, was purchased by the Royal Irish Academy in 1844.

The monastery survived numerous attacks from Irish, Vikings and Normans. Rivalry between the monasteries was not uncommon; Clonmacnoise engaged Durrow in a major pitched battle and slew two hundred of the latter’s fighting men. Almost a hundred years later, the King of Cashel, Felim Mac Criffan, plundered Clonmacnoise three times; one of these times, in 833, he is said to have ‘butchered the monks like sheep.’ Evidently Mac Criffan experienced some sort of conversion experience, however, for, following a life of attacking other monasteries, such as Durrow and Kildare, he is listed in the Annals of Ulster as optimus Scotorum,’ ‘the best of the Irish – as scribe and an anchorite.’ Clonmacnoise was also plundered and burned on at least ten occasions by the Vikings. In 884, one of these Viking leaders, Turgesius, burned down the monastery, after his wife, Ota, danced naked on the high altar and engaged in other lewd and idolatrous acts. Between 832 and 1204, it was attacked thirty-three times and finally reduced to ruins by the English in 1552 when it was claimed, according to an annalist, ‘not a bell, large or small, an image or an altar, a book or a gem, or even a glass in a window, was left which was not carried away.’ A hundred years later, to add to this tragedy, the notoriously vicious Oliver Cromwell, himself, returned with his army and cannonaded the site.

The ruins are the most extensive in Ireland, consisting of a Cathedral, eight churches, two round towers, three high crosses, two hundred grave slabs and a 13th century castle. The nuns church a 12th century Irish-Romanesque building with a simple church and only a knave and chancel. The chancel arch is carved with geometrical patterns in three orders. The church was built-in 1167 by Dervorgilla, the wife of a Breifne King, Tiernan O’Rourke (Ua Ruairc), whose abduction by Diarmait Mac Murchada (Strongbow) king of Leinster, was one of the contributory factors leading to the Anglo-Norman invasion of Ireland.

Underwater in The Shannon near Clonmacnoise archaeologists found the remains of a wooden bridge, built-in 804 AD, it is 533 ft long and 17 ft wide.

Still Clonmacnoise was never really destroyed. At one time listed as one of the four most sacred of pilgrimage sites in Ireland, it actually has a longer history of pilgrimages than any other. The first pilgrim recorded at Clonmacnoise was noted in the annals as having died in 606 CE. The burial-place of many named and unnamed Christians, pilgrims, monks, and kings, including Rory O’Connor, the last high king of Ireland.

Image | Aerial photo of Clonmacnoise, Co Offaly || CertiPhones.com – More Care Less Cost