The Round Towers of Ireland, for instance, have formed a greater puzzle to antiquaries than the churches of Hexham or Lindisfarne--partly because of their antiquity, and partly from their unlikeness to any local buildings of the time. The theories in regard to them are wild beyond all probability. They have been attributed: (1) By Henry O'Brien to the Tuatha De Danaan, a Persian colony which is supposed to have built them for phallic worship. (2) By Vellaney to the Phœnicians, the buildings being afterwards used by the Druids as fire-towers. (3) By Dr. Lynch, Peter Walsh, Molyneux, etc., to the Danes, as war-towers. Petrie, with clearer arguments, claims them as Christian. In his Prize Essay on the origin and uses of the Round Towers (A.D. 1820) he proves that no buildings except these towers were known to have cement in pre-Christian Ireland. For the Pagans and Druids have left us the great fortresses of Dun Ængus, and Dun Connor on Aran Mor, and the great sepulchres of Dowth and New Grange, all built without cement and of unhewn stones. Now the Round Towers are of hewn stones closely fitted and cemented, till they are solid as a rock, standing firm as ever, after their fifteen centuries of existence. They are called in Ireland by the generic name of "cloic-theack," or bell-house, and are invariably found close to the ruins of a monastery or a church. In some cases, like the one at Clonmacnoise, the church has entirely disappeared, leaving only the graveyard to mark its site, and in the graveyard a veritable Comacine cross! It cannot be proved that the towers belong to an earlier age than the churches attached, for we have a witness in the ruins themselves. The masonry of the tower and the remaining walls of the church at Kilmacduagh is identical, as are the later tower and church-porch at Roscrea--_i.e._ good, solid _opus gallicum_. Miss Stokes and the Rev. John Healy uphold the theory[123] of their being towers of refuge in warlike times. They may well have been used as such, on account of their strength, and also their proximity to the churches, which were always, in the Middle Ages, inviolable cities of refuge. This, however, does not affect our question as to how the towers came into Ireland, and whence came their builders. In the first place, where can similar towers be found dating from times contemporary? The answer is decided: in Italy. In Ravenna and Lombardy, from the date A.D. 300 to the fifth and sixth centuries; and they show just that Eastern touch which distinguishes the Byzantine-Roman architecture at Ravenna, and has caused authors to seek the origin of the Round Towers further east than Italy.