I am quite aware that my opinion on such a subject could have little weight.  To form a decided opinion on this subject, would require many years’ study; but when one of these gentlemen, the Earl of Dunraven, distinguished for his devotion to archaeology, writes to me that both Irish, English, and Continental scholars are all but unanimous in ascribing a Christian origin to these remarkable buildings, I cannot but feel that I am bound to accept this opinion, thus supported by an overwhelming weight of authority.  It may, however, be interesting to some persons to retain an account of the opposing theories, and for this reason I still insert page 115 of the original edition, only making such modifications as my change of opinion make necessary.

The theories which have been advanced on this subject may be classified under seven heads—­

(1) That the Phoenicians erected them for fire temples.

(2) That the Christians built them for bell towers.

(3) That the Magians used them for astronomical purposes.

(4) That they were for Christian anchorites to shut themselves up in.

(5) That they were penitentiaries.

(6) That the Druids used them to proclaim their festivals.

(7) That the Christians used them to keep their church plate and treasures.

[Illustration:  URN AND ITS CONTENTS FOUND IN A CROMLECH IN THE PHOENIX PARK, DUBLIN.]

Contradictory as these statements appear, they may easily be ranged into two separate theories of pagan or Christian origin.  Dr. Petrie has been the great supporter of the latter opinion, now almost generally received.  He founds his opinion:  (1) On the assumption that the Irish did not know the use of lime mortar before the time of St. Patrick.  For this assumption, however, he gives no evidence. (2) On the presence of certain Christian emblems on some of these towers, notably at Donaghmore and Antrim.  But the presence of Christian emblems, like the cross on the Ogham stones, may merely indicate that Christians wished to consecrate them to Christian use. (3) On the assumption that they were used as keeps or monastic castles, in which church plate was concealed, or wherein the clergy could shelter themselves from the fury of Danes, or other invaders.  But it is obvious that towers would have been built in a different fashion had such been the object of those who erected them.  The late Mr. D’Alton has been the most moderate and judicious advocate of their pagan origin.  He rests his theory (1) on certain statements in our annals, which, if true, must at once decide the dispute.  The Annals of Ulster mention the destruction of fifty-seven of them in consequence of a severe earthquake, A.D. 448.  He adduces the testimony of Giraldus Cambrensis, who confirms the account of the origin of Lough Neagh by an inundation, A.D. 65, and adds:  “It is no improbable testimony to this event, that the fishermen beheld the religious towers (turres ecclesiasticas),