The chief king of the Northern Ui Néill was called king of Aileach, from the prehistoric stone fortress of Aileach near Derry, which was occupied by kings of that line as late as the tenth century. They are sometimes called kings of the Fochla, _fochla_ being an old Irish word meaning the North. Their territory in the fifth century comprised the county of Donegal and possibly also Cairbre's country, the northern limb of Co. Sligo. The eastern side of Ulster nominally constituted another chief kingdom, which was regarded as the remnant of the ancient Ulster, and so is sometimes called by chroniclers "the Fifth" or "Conchubhar's Fifth." It seems, however, to have consisted of four practically independent kingdoms, no one of which held any permanent authority over the others. These were Dál Riada in the North-East, on the Antrim seaboard; Ulaidh, on the Down seaboard--retaining the name of the ancient dominant people of Ulster; Dál Araidhe, at the head of a Pictish people, occupying the inland parts of Down and Antrim and also the Derry side of the Bann valley from Loch Neagh northward to the sea; and Conaille, likewise a Pictish kingdom, in the north of Co. Louth. The remainder of Ulster, excluding Breifne, the kingdom of Aileach, and the eastern group, formed the kingdom of Airghialla or "Oriel." It should be borne in mind that this ancient Oriel of the fifth century extended northward to the mouth of Loch Foyle, and included the present Tyrone and most of Co. Derry, which were afterwards annexed to the kingdom of Aileach. The territories of the Southern Ui Néill lay in the counties of Meath, Westmeath, Longford, King's County, and Kildare; they were not continuous, being merely appropriated portions of the kingdom of Tara. Connacht extended eastward to the Erne and its lakes and to Loch Ramor in Co. Cavan. Munster comprised its present extent and also the two southern baronies of King's County. The northern boundary of Leinster ran by the Liffey, its tributary the Rye, south of the barony of Carbury in Co. Kildare, and included part of King's County bordering on Queen's County and Kildare. There were then seven chief kingdoms in Ireland, each of them containing a number of minor kingdoms. The seven chief kingdoms were (1) the kingdom of Tara, the midlands east of the Shannon; (2) the kingdom of Leinster; (3) the kingdom of Cashel or of Munster; (4) the kingdom of Cruachain or of Connacht; (5) the kingdom of Aileach, the Fochla, or the Northern Ui Néill; (6) the kingdom of Ulaidh or the lesser Ulster; (7) the kingdom of Oriel.