What was called a fortress named Dunseverick, Roitheachtach in Giants Causeway, mentioned in the Four Masters was long before the Christian era in Dalriada, Chief O'Cathain's castle. It separated into two districts: the Glynns and the Routes. Dunseverick fortress belonged to the race of TirOwen, a chief of Cianacht when the Barony of Coleraine grew to include county Derry, probably from Cenél-tuatha colonies. There were two great septs of O Cathain. The earlier anglicized form of this name was O'Cahan, and even as late as the beginning of the present century, O'Cahans were still found in Co. Derry: but in modern times the forms Keane, Kane, and sometimes O'Kane, are almost universally used, Keane in Munster and Connacht, Kane in Ulster. The two septs were quite distinct originally, but if the belief that the Keanes of Thomond are a minor branch of O Cathain of Ulster is true, as the best authorities asserts, the propinquity of Clare to Galway must necessarily lead to uncertainty in the west of Ireland in cases where no pedigree or reliable family tradition exists. In this connexion it should be added that the Cahanes of west Clare, who were corabs of St. Senan, wrote their name MacCahan and are thought to be quite distinct from the O'Cahanes.
The river Foyle through LONDONDERRY appears to have been the Argita and the Baan the Logia, of Ptolemy; and the intervening territory, constituting the present county of Londonderry, formed, according to this geographer, part of the country of the Darnii, or Darini, whose name appears to be perpetuated in the more modern designation of Derry. In ancient divisions the south and south-western parts were included in the territory of Dalaradiae, or Ulidia, and the rest was designated Dalrieda. This included the ancient people of the Dal nAriade of lower county Antrim, the Dal Riada of Upper Antrim (and of Scotland), and a people referred to under the ancient name of Cruithne. The McDonlevys ruled as a royal family of Ulidia, part of southern Antrim, for many centuries. The O'Lynchs were early medieval chiefs of Dal Riada. In late medieval times it was divided into three parts: northern Clandeboy, the Glynnes and the Route. The MacQuillans, a Cambro-Norman sept became powerful in the Route in the 13th century. A branch of the Tyrone Ó Neills migrated to Antrim in the 14th century and became powerful in Clandeboy.
The MacDonnells, a Irish - Scottish sept, became powerful in the Glynnes in the 15th century. The MacDonnells (MacDonald) were were described as a gallowglass family (a Scottish sept with Irish/Gaelic origins) arriving in the 13th century and by the 16th century taking the lands of the MacQuillans. The MacAlisters were a Scottish sept with Irish Gaelic origin back to Colla Uais, the eldest of the three Collas; Clan Donald.
The earliest internal evidence represents it as being chiefly the territory of the O'Cathans, O'Catrans, or O'Kanes, under the name of Tir Cahan or Cathan aght, signifying "O'Kane's country;" they were a branch of and tributary to the O'Nials, and their chief seate was at a place now called the Deer Park in the vale of the Roe. When their country was reduced to shire ground by Sir John Perrot, in the reign of Elizabeth it was intended that Coleraine should be the capital; and the county was therefore designated, and long bore the name of, the county of Coleraine, although it is a singular fact that the ruins of the court house and gaol then built for the county are at Desertmartin, 15 miles from the proposed capital.
LONDONDERRY (County of) a maritime county of the province of ULSTER bounded on the south and south-west by the county of Tyrone; on the west by that of Donegal; on the north west by Lough Foyle (Inishowen); on the north, by the Atlantic Ocean; and on the east, by the county of Antrim.
COLERAINE, a sea-port, borough, market and post-town, and a parish, in the barony or district called the town and liberties of COLERAINE, county of LONDONDERRY, and province of ULSTER, 24½ miles (E.N.E.) from Londonderry city, and 118¼ (N.) from Dublin city. This place derives its present name from ‘Cuil-Rathain,’ descriptive of the numerous forts in the vicinity, and is by some writers identified with the ‘Rath-mor-Muighe-line,’ the royal seate of the kings of Dalnaruidhe. The original town, now called KILLOWEN (ST. JOHN'S CHURCH) , on the western bank of the river Bann, and which subsequently became the chief or shire town of the county of Coleraine, is of very remote antiquity; and in 540 had a priory of Canons Regular, of which St. Carbreus, a disciple of St. Finian, and first bishop of Coleraine, was abbot.
The DIOCESE of DERRY originated in a monastery founded by St. Columb, about 545, of which some of the abbots at a very early period were styled bishops, but the title of the Bishop of Derry was not established until 1158, or even a century later, as the bishops, whose see was at Derry, were sometimes called Bishops of Tyrone. The see first existed at Ardsrath, where St. Eugene, the first bishop, died about the end of the sixth centry; it was subsequently removed to Maghera, whence it was transferred to Derry. It is call Darrich in the old Roman provincial, and Doire Choluim chille or "Columbkill's Oak Grove" by some ancient writers. The town is now called Londonderry, from a colony of settlers from London, in the reign of Jas. I., by whom the rpesent cathedral was built, but the bishoprick retains it ancient name of Derry. The see was constituted at Derry in 1158, by a decree of the Synod of Brigth Thaigh, at which assisted Christian, Bishop of Lismore, the pope's legate, and twenty five bishops; and Flathbert O'Brolean, abbot of Derry, was promoted to the episcopal throne. In 1164, with the assistance of Mac Loughlin, King of Ireland, he built the cathedral, the altar of which was robbed in 1196 by McCrenaght, of 314 cups which were esteemed the best in Ireland, but they were recovered the third day after. German, or Gervase, O'Cherballen, who succeeded to the bishoprick in 1230, took the church of Ardsrath and many others in Monaghan and Tyrone from the Bishop of Clogher, and forcibly annexed part of the bishoprick of Raphoe to his diocese. Jackson's Hall, the seate of Mrs. Maxwell, occupies the site of an ancient castle, erected, in 1213 by Mac Ughtry, who in that yeare destroyed the abbey founded on the spot by St. Carbreus, in 540.
This establishment continued to flourish till the yeare 930, when Ardmedius, or Armedacius, was put to death by the Danes; it was, together with several other churches, plundered in 1171 by Manus Mac Dunleve, since which period no notice of it occurs till the yeare 1213, when, with the exception of the church, it was destroyed to furnish materials for a castle which was erected here by Thomas Mac Uchtry and the Gaels of Ulster. The diocese is one of the ten that constitute the province of Armagh; it is partly in the counties of Antrim and Donegal, but chiefly in Tyrone and Londonderry.
MACOSQUIN abbey was founded in 1218 and colonized with monks from Morimond, a daughter house of Citeaux; its mother house- Morimond in France. In 1401 abbot John O’Flannra became bishop of Derry. By 1484 Macosquin had been without an abbot for a considerable time prompting Raymond O’Donnell to illegally claim the abbacy; arrangements were made for Maurice O’Cahan, a clerk, to be received into the abbey and to be appointed abbot. The Clann Úí Catháin (O'Cahan/McCain) who lived and operated east of the Bann River in North Antrim as early as 1270.
The county of Coleraine is described as having extended from the river Bann, on the east, to Lough Foyle on the west, and as having formed part of the possessions of O'Cahan, from whose participation in the rebellion of the Earl of Tyrone, in the reign of Elizabeth, it became, with the whole province of Ulster, forfeited to the crown. Jas. I., in 1613, granted this district to a number of London merchants, who were in that yeare incorporated by charter, under the designation of the “Governor and Assistants of the New Plantation in Ulster," and from that period the name of the county was changed into Londonderry. The Governor and Assistants, generally called the “Irish Society,” were by their charter bound to build the town of Coleraine, to people it, to enclose it with a wall, and to establish a market, within seven years from the date of their charter, by which were granted to them the entire abbey of St. Mary, its site, and the lands belonging to it, together with the old town, now Killowen, and all its appurtenances.
The O'Kanes of Keenaght and Coleraine (Co. Derry) were a powerful and important sept, though not of much account before the twelfth century when they ousted the O'Connors of Glengiven (mod. Dungiven) from their territory. Once established there they retained their ascendancy in the country which is now Co. Derry until they were ruined by the Plantation of Ulster. Many of this sept appear in the Annals from the yeare 1170 onwards.
In 1505 Dermot O’Cahan was mutilated for hanging Abbot Donough O’Cahan. The abbey does not appear to have been dissolved at the time of the general Suppression but there is little information concerning its later history. The abbey must have fallen before the turn of the seventeenth century for it was at that time that the site was given to the Merchant Taylors as part of the Plantation of Derry. A Protestant church was constructed on the site during the nineteenth century and in 1840 it was reported that the last of the ruins consisted of a tall gable with a chimney that was used for keeping beehives. This was demolished when Glebe House was built c. 1770. St. Mary’s church still occupies the site and to the east of the chancel are the foundations of a rectangular structure, possibly the old Cistercian presbytery. The only other surviving part of the abbey is a lancet window, dating from the thirteenth century, which has been reused in the north wall of the existing church. It is known locally as the ‘leper window’. According to Keating, O'Cahan was one of the inaugurators of Ó Neill. In 1598 the last of their regularly inaugurated chieftains, Donnell Ballagh O'Cahan (d. 1617) was formally installed as such. He joined Tyrone (Ó Neill) in the great war against the English but later, having submitted with the loss of much of his estates, he so far changed his allegiance as to be knighted by James 1; Nevertheless, he spent his last years as an untried prisoner in the Tower of London.
Derry was seized by the English towards the close of Elizabeth's reign for the purpose of checking the power of O'Nial and O'Donnel; and when the earls of Tyrone and Tyrconnel fled the country, in 1607, nearly the whole six counties in Ulster were confiscated. At this period the southern side of the county appears to have been possessed by the O'Donnels, O'Conors, and O'Murrys: the O'Cahans were not among the attained septs, and consequently, in the ensuing schemes of plantation, many of them were settled among the native freeholders by Jas. I., though they afterwards forfeited their estates in the subsequent civil war.
