The little cathedral city of Armagh is one of the most famous places in all Ireland. Yet Armagh has suffered more than its fair share of disasters during Ireland's troubled history. Accidental fires destroyed it in 617 and again in 670; tribal warfare, the Danish invasions and the various English wars took heavy toll of it. It was a place of some importance from very early times, and is said to derive its name of Ard Macha, or Hill of Macha, from an ancient queen, one of three bearing that name said to be buried on the hill now crowned by the old cathedral. In 352 B.C., a later Queen Macha founded the fortress Emhuin Macha, latinized Emania, the place now being known as Navan Fort near Armagh. The seate of the kings and queens of Ulster, it lasted for 700 years and was destroyed in the fourth century A.D. About one hundred years later, the foundation of Armagh as a town followed the arrival of St. Patrick; Daire, the chieftain of the district, provided a site for a church, which was duly built in roughly the position now covered by the Bank of Ireland and its gardens. Apparently, an important synod was held at Armagh in or about 448, and it is also reported that Armagh was a renowned seate of learning in the Dark Ages. Astronomy may well have been taught there. The Bishops of Armagh retired to Drogheda.

ARMAGH is supposed to have been part of that named by Ptolemy as the territories of the Vinderiiâ and Voluntii: it afterwards formed part of the district called Orgial, which also comprised the counties of Louth and Monaghan. The formation of this part of Ireland into a separate dominion is said to have taken place so early as the yeare 332, after the battle of Achaighleth-dergâ, in Fermoy, in which, as recorded by Tigernach, abbot of Clonmacnois, who died in 1068, Fergus Feagha, son of Froechair the Brave, the last of the Ultonian kings who resided in Eamania, was killed by the three Collas, who then expelled the Ultonians from that part of the province to the south of Lough Neagh, and formed it into an independent state, to which they gave the name of Orgial, afterwards corrupted into Oriel or Uriel, names by which it was distinguished to the beginning of the seventeenth century. The northern verge of the county, near Lough Neagh, the north-western adjoining Tyrone, and the neighbourhoods of Armagh, Market-hill, and Tanderagee. The county is partly in the diocese of Dromore, but chiefly in that of Armagh. An inland navigation along the border of the counties of Armagh and Down, from Newry to Lough Neagh, by the aid of the Bann and the Newry water, was the first line of canal executed in Ireland-the Durham, Hereford, North Devon, Leicester, Ayrhsire, and other breeds of cattle have been introduced.

As the first Anglo-Norman adventurers who came to Ireland showed very little scruple in despoiling the churches and monasteries, Armagh suffered considerably from their depredations and the clergy were almost reduced to beggary. When the English kings got a footing in the country, they began to interfere in the election of bishops and a contest arose between King John and the Pope regarding Eugene Mac Gillaweer, elected to the primatial see in 1203. This prelate was present at the General Council of the Lateran in 1215 and died at Rome the following year. The English kings also began to claim possession of the temporalities of the sees during vacancies and to insist on the newly-elected bishops suing them humbly for their restitution. Primate Reginald (1247-56), a Dominican, obtained a papal Brief uniting the county of Louth to the See of Armagh. Primate Patrick O'Scanlan (1261-70), also a Dominican, rebuilt to a large extent the cathedral of Armagh and founded a house for Franciscans in that city. Primate Nicholas Mac Maelisu (1272-1302) signalized himself by convening an important assembly of the bishops and clergy of Ireland at Tuam in 1291, at which they bound themselves by solemn oaths to resist the encroachments of the secular power. Primate Richard Fitz-Ralph (1346-60) contended publicly both in Ireland and England with the Mendicant Friars on the question of their vows and privileges. A contest regarding the primacy of Armagh was carried on intermittently during these centuries by the Archbishops of Dublin and Cashel, especially the former as the city of Dublin was the civic metropolis of the kingdom. There is a Franciscan and an Augustinian friary in Drogheda, Mellifont, and the Dominicans have one founded by Primate Netterville in 1224. They also have one in Dundalk, established originally at Carlingford in the early part of the fourteenth century.

During the English period, the primates rarely visited the city of Armagh, preferring to reside at the arch-episcopal manors of Dromiskin and Termonfechan, in the county of Louth which was within the Pale. During the reign of Henry VIII, Primate Cromer, being suspected of heresy by the Holy See, was deposed in favour of Robert Wauchope (1539-51), a distinguished theologian, who assisted at the Council of Trent. In the meantime, George Dowdall, a zealous supporter of Henry, had been intruded into the See of Armagh by that monarch, but on the introduction of Protestantism into Ireland in the reign of Edward VI, he left the kingdom in disgust. Thereupon the king in 1552, appointed Hugh Goodacre to the see. He was the first Protestant prelate who assumed the title of Primate and enjoyed the temporalities of the diocese. In the beginning of the reign of Queen Mary, Dowdall (1553-58) was appointed by the Pope to the see on account of the great zeal he had shown against Protestantism, though at the same time, he had acted in a schismatical way.

John O'Donovan, in his notes to the yeare 1178 of his edition of the Annals of the Four Masters, describes the territory of the Airghialla:

"Keating, Duald Mac Firbis, O'Flaherty, and all the ancient Bardic writers of the history of Ireland, state that the three Collas, who formed the territory of Oriel, deprived the Ultonians of that portion of their kingdom extending from Gleann Righ, and Loch n-Eatach, westwards. The general opinion was that the territory of Oirghiall, or Oriel, comprised the present counties of Louth, Armagh and Monaghan, and that Uladh or Ulidia, the circumscribed territory of the Clanna Rury, was, when formed into shire-ground, styled the County of Down, from Down, its principal town. This having been established, the editor, during his examination of the ancient topography of Ulster, was led to look for Glenree somewhere on the boundary between the counties of Armagh and Down; and, accordingly, on examining the documents, he found that, on an ancient map of the country lying between Lough Erne and Dundalk, preserved in the State Papers' Office, the vale of the Newry River is called 'Glenree,' and the river itself 'Owen Glenree fluvius.' He also found that in the Ulster Inquisitions the remarkable place near Newry called Fathom, is denominated Glenree Magafee. Oriel, or Oirghialla, anciently extended from this Glenree to Lough Erne, and comprised the counties of Louth, Armagh, Monaghan, and in later ages the whole of the County of Fermanagh, as we learn from O'Dugan, who, in his topographical poem, places Tooraah, the country of O'Flanagan, in the north-west of Fermanagh; Lurg, the country of Muldoon, in the north of the same County; and the entire of Maguire's country in it. That the County of Fermanagh was considered a part of Oriel, at least since the Maguires got possession of it, is further corroborated by the fact, that throughout these Annals Maguire is called the pillar and prop of the Oriel. It is stated in a manuscript in Trinity College, Dublin (H.3, 18. p.783), that the boundary between Oriel and Ulidia, or the Clann Colla and the Clann Rury, or ancient Ultonians, was made in the west side of Glenree from Newry upwards, and that the Clanna Rury never extended their boundaries beyond it. This boundary, which consists of a fosse and rampart of great extent, still remains in some places in tolerable preservation, and is called by the strange name of the Dane's Cast, in English, and ... Valley of the Black Pig in Irish. For a minute description of the ancient boundary the reader is referred to Stuart's Historical Memoirs of the City of Armagh, Appendix, No. III., pp. 585, 586."