CTTY OF LONDONDERRY. 
1589, when Red Hugh O’Donnell plundered Thomond, the territory of the O’Briens, who 
were then leagued with Queen Elizabeth, Mac Brody their chief poet and historian, as the 
Four Masters record in their annals, wrote that it was in revenge of the destruction of Aileach 
by Mortagh O'Brien that God, in consequence of the curse of Columbkille upon his race, per¬ 
mitted Thomond to be so dreadfully devastated. 
It will have been seen that the preceding notices of Aileach have been drawn entirely 
from Irish authorities, but it should also be stated, that there are strong grounds for believing 
that its existence as a royal seat or town was, as might naturally be expected, not unknown to 
Ptolemy, the Greek geographer of the second century, in whose map of Ireland it appears to 
be marked under the appropriate classical name of Regia , and situated on the west of his 
river Argita, which seems to be a translation of the Irish word Fin, the name of the principal 
or parent stream of Lough Foyle. It is not a solid objection to this supposition, that the 
situation of Ptolemy’s Regia is not laid down with perfect accuracy. In a map which must 
have been drawn entirely from the reports of merchants or mariners, no exact position in 
localities should be expected, and certainly is found in no one instance. We should, perhaps, 
rather wonder at Ptolemy’s general accuracy, when we consider that all the maps of Ireland, 
from the time of Norden and Jobson, in the reign of Elizabeth, down to the survey by 
Sir William Petty, often misname, and sometimes lay down, remarkable places altogether out 
of their proper localities : and it is a remarkable fact, that even in our own times the situation 
of Aileach is marked, by two of the most distinguished Irish scholars and topographers, 
Charles O’Conor and Haliday—as far from the actual locality of the palace as Ptolemy places 
his Regia. 
It may, perhaps, be further objected that—though Ware, and most other antiquaries and 
geographers of the 17th century, concurred in the opinion that the Argita of Ptolemy was the 
Fin, or river of Lough Foyle, and his Vidua, Lough Swilly, Camden—on the contrary, con¬ 
jectured the Argita to have been the Swilly, and the Vidua the Crodagh, a small river in 
Donegal—and that this conjecture is corroborated by the map of Richard of Cirencester—said 
to be drawn from ancient authorities in the 14th century—which was unknown to Camden, 
having been but recently discovered. To this objection it may be replied, that the authority 
of Camden alone should be held as of little consideration in this inquiry, as his conjectures 
respecting the locality of Ptolemy’s names in Ireland are in most instances erroneous, and that 
to concur with him on this occasion, we should also give assent to the supposition of the 
Rev. Charles O'Conor and others, that the Logia of Ptolemy is Lough Foyle, though it seems 
beyond question to he the Lagan, which is called Locha by the ancient Irish, and Logan by 
the early English writers. Neither does the authority of Richard add any great weight to 
Camden’s conjecture, though the difficulty is lessened by that writer, who throws into his map, 
between the Argita and Logia, as if they had been omitted by Ptolemy, not only the Banna or 
Bann, but also the Foyle, to which he gives the very suspicious name of Derabhona, or river 
of Derry. For, in the first place, it may be remarked, that his authority has been lately im¬ 
pugned, and in the second, that—even allowing his work to be genuine, as Stukely and Pinkerton 
believed—it would still be as the latter observes, the height of absurdity to set his authority 
against that of Ptolemy when he differs from him. Be this, however, as it may, it is worthy 
of remark, that Richard, in transferring the Argita of Ptolemy to Lough Swilly, and inserting 
the Derabhona in its place, marks a city, which, though without a name, is evidently the 
Regia of Ptolemy in the exact situation of Aileach—namely, between the Derabhona, or Derry 
river, and the Argita, which is his Lough Swilly. 
In conclusion—if the Regia of Ptolemy be considered, from the preceding evidences, as 
the Aileach Neid of Irish history, a point of great importance will be gained towards the 
general elucidation of the map of Ireland by that ancient geographer: may it not be added, 
that no other conjecture will combine so many plausible and concurrent evidences of pro¬ 
bability in its favour ? 
