Irish round tower

Irish round towers (Irish: Cloigtheach (singular), Cloigthithe (plural) – literally "bell house") are early medieval stone towers of a type found mainly in Ireland, with two in Scotland and one on the Isle of Man. Though there is no certain agreement as to their purpose, it is thought that they may have been bell towers, places of refuge, or both.

Generally found in the vicinity of a church or monastery, the door of the tower faces the west doorway of the church. In this way it has been possible to determine without excavation the approximate site of lost churches, where the tower still exists.

Surviving towers range in height from 18 metres (59 ft) to 40 metres (130 ft), and 12 metres (39 ft) to 18 metres (59 ft) in circumference; that at Kilmacduagh being the highest surviving in Ireland (and leaning 1.7 metres (5 ft 7 in) out of perpendicular). The masonry differs according to date, the earliest examples being uncut rubble, while the later ones are of neatly joined stone work. The lower portion is solid masonry with a single door raised two to three metres above, often accessible only by a ladder. Within, in some, are two or more floors (or signs of where such floors existed), usually of wood, and it is thought that there were ladders in between. The windows, which are high up, are slits in the stone. The cap (roof), is of stone, usually conical in shape, although some of the towers are now crowned by a later circle of battlements.

The main reason for the entrance-way being built above ground level was to maintain the structural integrity of the building rather than for defence. The towers were generally built with very little foundation. The tower at Monasterboice has an underground foundation of only sixty centimetres. Building the door at ground level would weaken the tower. The buildings still stand today because their round shape is gale-resistant and the section of the tower underneath the entrance is packed with soil and stones.

The distance from the ground to the raised doorway is somewhat greater than that from the first floor to the second; thus large, rigid steps would be too large for the door. Excavations in the 1990s, revealing postholes, confirm that wooden steps were built. However, the use of ladders prior to the construction of such steps cannot be ruled out.

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