The substantial remains of Clonmacnois, pre-Norman Ireland’s most important Christian site, enjoy an idyllic location on the grassy banks of the gently meandering Shannon. Here the river descends at a shallow gradient through flat land that floods extensively in winter, but in spring, the receding flow leaves beautiful, nutrient-rich water meadows, some of the last of their type in Europe. The Shannon Callows, as they are known, become the summer home of rare wild-flowers, grazing cattle, lapwings, curlews, redshanks and rare corncrakes.

The monastery was founded, as a satellite of St Enda’s house on Inishmore, in around 548 by St Kieran (Ciarán), who with the help of Diarmuid of the Uí Néills, the first Christian High King of Ireland, erected a wooden church here. Kieran brought with him a dun cow, whose hide later became Clonmacnois’ major relic – anyone who died lying on it would be spared the torments of Hell – and who was commemorated in the Lebor na hUidre (Book of the Dun Cow), the oldest surviving manuscript written wholly in Irish. Perfectly sited at the junction of the Slí Mhor, the main road from Dublin Bay to Galway Bay, and the major north–south artery, the Shannon, the monastery grew in influence as various provincial kings endowed it with churches and high crosses. With a large lay population, Clonmacnois resembled a small town, where craftsmen and scholars produced illuminated manuscripts, croziers and other remarkable artefacts, many of which can be seen in the National Museum in Dublin. However, between the eighth and twelfth centuries the site was plundered over forty times by Vikings, Anglo-Normans and Irish enemies, and church reforms in the thirteenth century greatly reduced its influence. In 1552, Athlone’s English garrison reduced it to ruins, though, as the burial place of Kieran, it has persisted to this day as a place of pilgrimage, focused on the saint’s day on September 9.

The visitor centre and high crosses

Clonmacnois’ three magnificent high crosses have been moved into the excellent visitor centre to prevent further damage by the weather. (Outside the Office of Public Works has erected all-too-faithful replicas, complete with erosion – an attempt to recreate their appearance when first carved would have been far more constructive.) The finest is the Cross of the Scriptures, a pictorial sermon showing the Crucifixion, Christ in the Tomb and the Last Judgment. It was erected in the early tenth century by Abbot Colman and Flann, the High King of Ireland, who may be depicted together (with Flann holding a pole) in the bottom scene on the shaft’s east face. Standing 4m high, the cross is carved from a single piece of sandstone and may originally have been coloured. The other two crosses are about a century older and much simpler, the South Cross featuring the Crucifixion surrounded by rich interlacing, spirals and bosses, while the North Cross is carved with abstract Celtic ornaments, humans and animals.

Elsewhere in the visitor centre there’s a good audiovisual on Kieran’s life and the history of Clonmacnois, and an interesting reconstruction of a dairthech (oak house), the type of small oratory that would have been built out of wood at this and other monasteries throughout Ireland before stone began to be used in the tenth century.

The site

Most of Clonmacnois’ nine churches are structurally intact apart from their roofs, the largest being the cathedral straight in front of the visitor centre. It was built in 909 by Abbot Colman and King Flann, but its most beautiful feature now is the fifteenth-century north doorway, featuring decorative Gothic carving surmounted by SS Dominic, Patrick and Francis. The last High King of Ireland, Rory O’Connor, was buried by the altar here in 1198. Several smaller churches encircle the cathedral, notably Temple Ciarán, the burial place of St Kieran, dating from the early tenth century.

In the western corner of the compound rises a fine round tower, erected in 1124 by Abbot O’Malone and Turlough O’Connor of Connacht, High King of Ireland and father of Rory. There’s another round tower attached to the nave of Temple Finghin, which is Romanesque in style and thought to date from 1160–70.

In a peaceful, leafy glade about 500m away from the main site and signposted from the east side of the compound, the Nun’s Church is the place to escape to if a fleet of tour coaches descends. Founded by Queen Devorguilla, who retired here as a penitent in 1170, it boasts a fine Romanesque doorway and chancel arch carved with geometrical patterns.