That the general conclusions embodied in this work were arrived at after a long and patient investigation, not only of the architectural peculiarities of the numerous round towers, but also of the ecclesiastical structures usually found in connection with them, is sufficiently shown by the many references to, and illustrations of, examples scattered over the whole country. But Petrie also, with the assistance of the best Celtic scholars in Ireland, sought in the ‘Annals’ and other Irish MSS. for references to such buildings as it was the custom of the early inhabitants to erect; and from these hitherto-neglected sources of information, much light was thrown upon the subject of ancient Irish ecclesiastical architecture. The following is a summary of Petrie’s conclusions:—
1. That the Irish ecclesiastics had, from a very early period, in connection with their cathedral and abbey churches, campaniles or detached belfries, called in the Irish ‘Annals’ and other ancient authorities by the term Cloictheach, ‘House of a bell.’
2. That no other building, either round or square, suited to the purpose of a belfry, has ever been found in connection with any church of an age anterior to the twelfth century, with the single exception of the square belfry attached to a church on Inis Clothrann or Clorin, an island in Lough Ree, which seems to be of earlier date.
3. That they were designed to answer at least a twofold purpose—to serve as belfries, and as keeps or places of strength, in which the sacred utensils, books, relics, and other valuables were deposited, and into which the ecclesiastics to whom they belonged could retire for security in cases of sudden attack.
4. An examination of ancient Irish literature tends strongly to the conclusion that the people so generally recognised this use of the round towers as a primary one, that they very rarely applied to a tower erected for defence any other term but that of ‘cloictheach’ or belfry.
5. That they were probably also used, when occasion required, as beacons and watch-towers.
Petrie, while establishing their ecclesiastical character and origin, gave, however, too wide a margin to the date of their erection, viz., from the sixth century to the thirteenth. The investigations of the late Lord Dunraven in tracing such structures on the Continent narrowed their first erection down to the ninth century. He shows that they were founded on European examples, the most notable being those of Ravenna, where six of its round towers still stand. The round towers were due to Byzantine influences, and some writers trace their original source to the towers built in connection with early Syrian churches. Miss Stokes, following Lord Dunraven, assigns the Irish round towers to three periods between 890 and 1238 A.D., and classifies them into four distinct groups, according to their style of masonry and doorways.
Doorway, Round Tower, Glendalough.
The Norse sea-rovers rendered ecclesiastical establishments most unsafe. The first period of their invasions extended from the end of the eighth century to the middle of the ninth century, and the land was ravaged from north to south with fire and sword. On the sea-coast and along the river valleys the country lay waste. On the banks of the Bann, the shores of Lough Neagh, by the Boyne, and broad expansions of the Shannon, and as far south as the distant Skellig Rock, few sacred establishments escaped plunder and desecration. To protect their churches, oratories, and sacred treasures, these towers were built by the monks, from which watch could be kept, and an easy retreat made to them as places of safety; their lines can still be traced along the shores of the waters where the fleets of the Danes are known to have appeared.