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Inside 'A history of Ireland in 100 words': Caistél

15 March 2020

What have the French got to do with Irish castles? Find out in today's entry on Irish, Viking and Norman architecture.

To celebrate Seachtain na Gaeilge we're letting you take a peek inside our book A history of Ireland in 100 wordsToday's entry is Caistél. 

The medieval Irish usually built their houses and churches in wood, and experimental archaeology has shown that these probably did not last beyond the lifetime of an individual. When they built in stone, they left magnificent structures to posterity.

Stone forts of the early medieval period dot the country. These were frequently designated by the word caisel. This is an early borrowing from Latin castellum ‘fort’, a word that ultimately makes its way into several European languages, including English as ‘castle’. The word caisel appears in many place-names, the most famous being Cashel, Co. Tipperary, although the buildings on the Rock of Cashel that survive today, such as Cormac’s Chapel, which was consecrated in 1134, belong to a much later period.

Stone castles, which became a feature of Irish architecture after the coming of the Anglo Normans in the twelfth century, were often termed caistél in Irish. Caistél is probably a borrowing from French castel, itself derived ultimately from the Latin castellum, just like caisel. Norman influence on Irish building can also be seen in the language of construction. Words associated with construction that probably derive from French include coirbél ‘corbel’, moirtél ‘mortar’, gísdáil ‘joisting’ and túr ‘tower, turret’. The regular Modern Irish word for ‘corner’, cúinne, may also fall into this category. It seems to have been borrowed from either French coing or English quoin, and with cloch ‘stone’ came to signify the all-important ‘cornerstone’ (cloch chúinne).

A more common alternative to caistél was caislén (Modern Irish caisleán). This word is now prominent in the Irish landscape in names such as Caisleán na Mainge (Castlemaine, Co. Kerry, that is, ‘the Castle of the River Maine’), and the very many places called Caisleán Nua (Newcastle), such as Caisleán Nua Thiar (Newcastle West, Co. Limerick). The castle after which Castlemaine takes its name was built by the Fitzgerald family in the thirteenth century. In the same place, there had been an earlier Viking fortification which was plundered by a king of a branch of the Munster dynasty based around the lakes of Killarney, Éoganacht Locha Léin, about 867. The term dún was used to refer to the earlier place. This word was more commonly used for a fort associated with an Irish chieftain (see also Lios) and survives in place names such as Doon, Co. Limerick. Generally made of earth rather than stone, a dún could house a residence within a fortified enclosure.

Dún was synonymous with the related word dúnad, though the latter was also used for an encampment of a more transitory nature. Such a camp was also known as a longphort (a compound of long ‘ship’ and port ‘place’). First found in connection with Vikings, it seems that a longphort could be a more substantial structure than a dúnad, and possible examples have been identified in the archaeological record, including Dunrally Fort, Co. Laois. This site was said to have been associated with a Viking leader, Rodolf, and was destroyed by an Irish king in 862. If Rodolf himself survived the attack, he may be identical with a similarly named Viking who was plundering around the River Rhine in the following year, but this must remain in the realm of speculation.

A history of Ireland in 100 words is a book, a banner campaign and an exhibition. Find our more at

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