"On the east, the Rhogbogdioi (see map below) occupy the area around the cape of Rhogbogion and may be related to the Dál Riata of early history who founded a kingdom in Argyll in Scotland in the fifth century. To the south of them are the Darinoi, whose name may be connected with the name Dáire, presumably an ancestor deity. It is interesting to note that Dundrum in County Down in the territory of the Dál Fiatach is known as Dun Droma Dáirine."
"Woluntioi is one of the more recognisable tribal names on the map. It is undoubtedly connected with the Ulaid, occupying an area between Isamnion, possibly Emain Macha, and the Buvinda (the Boyne river) on Ptolemy's map. In the early historic period they were known as the Dál Fiatach and occupied the area between Dundrum Bay and Belfast Lough. Their historic centre was at Dún-Dá-Lethglass (Downpatrick), originally a secular rather than a religious site."Archaeology Ireland, Heritage Guide No. 21 - Ireland in the Iron Age Map of Ireland by Claudius Ptolemaeus
"This study of the people known as Dál Fiatach, or Ulaid, is not a history of Ulster as a whole. They and the Dál Araidi were the two leading population-groups in N.E. Ireland from the third to the twelfth centuries. The ancient name of Ulster was Ulad, and it included the whole country north of the Boyne and across to the Shannon. It subsequently shrank to the limits of the present counties of Antrim and Down. The Dál Fiatach were predominant in Down. Their records were kept in the monasteries of Saul and Downpatrick and have survived in a compilation of history, tradition and genealogies, known as Senchus Sil hIr. There are other sources for their history, viz., the Annals, the Ban-shenchus, the lives of saints."
"They hold an important place in the life of St. Patrick, for when he landed at Inber Slainge in Loch Cuan, i.e. Strangford Lough, he landed in Dál Fiatach territory. His first converts in Ulster were people of this stock. Dichu was a chieftain of Dál Fiatach. His brother, Ros, helped Patrick to revise the Senchus Mor. They and their kindred held all East Down and the Ards. The early monasteries and schools of Bangor, Moville, Nendrum, Saul, grew up in their midst. St. Finnian of Moville, St. Domongort and St. Tuan of Boirche, St. Mael Cethir of Kerry, Iarlathi, third bishop of Armagh after Patrick, St. Samthann, all traced their descent from Dál Fiatach."
"Members of the race have left their names on the map to this day in Slieve Donard, Ben Madigan, Glengormly, Rademan, Dunsy Island. In the Annals and the Book of Rights they are the leading people in east Ulster from 600 a.d. down to the Norman invasion, 'The Irish have twelve kindreds of noble birth : six in Leth Cuinn = Northern Eire, Dál Cuinn, Dál Cúin, Dál Araidi who are the Picts, Dál Fiatach who are the Ulaid'. Professor McNeill considers this statement to be of great antiquity."Margaret Dobbs - The Dál Fiatach
The Dál Fiatach were the principal tribe (Tuath in Irish) in ancient Ulster and were located in the eastern part of County Down. They provided the majority of kings of Ulster from at least the time of Christ. The name meant the 'Share of Fiatach' after a king called Fiatach Finn or Fiatach the Fair, who died about 50 AD. Scholars are not sure that Fiatach was a real person or an ancestor that was made up later by his descendants who were the main line of the kings of Ulster until 1200 AD.
The ancestry of the kings of Ulster is traced back from 1200 AD, through the time of Saint Patrick, and back to Fiatach. Fiatach's own line is traced back to the Gods, the last two of which are called 'Old' the son of 'Too Old' and would have lived around 350 BC which is a time of important archaeological discoveries in Ulster. Fiatach is listed as Fiatach Finn mac Dáire or the son of Dáire which may be the ancestor god of the Dál Fiatach because the name is shown on Ptolemy's map of Ireland in eastern County Down. This pedigree is generally believed to be reliable from the time of Saint Patrick, although there is much literature about earlier kings. The reason that the time of Saint Patrick is accepted is because he lived and died among the Dál Fiatach kings and is buried in their old capital of Dún Lethglaise (now called Downpatrick after him) in eastern County Down.
This verse was written in a text of Féineachas ('Brehon Law') in the 8th Century:
Batar trí prímcheinéla i nHére, .i. Féini 7 Ulaith 7 Gáilni .i. Laigin.
There were three primary kinships in Ireland, i.e., the Féini and Ulaidh and Gáilióin, i.e., the Laighin.
These three kinships which have been remembered for two millenia through poems and stories, have been associated in recent times with four ancient Iron Age sites located in the central area of Ireland.
Almost all Gaelic manuscripts and all Catholic records were destroyed by the Gall (foreigners) from the Norman invasion of Ireland in 1169 until 1782 and the liberal period of Grattan's Parliament.
There are only a few sources of population records before then and no real surviving census until 1901. The National Archives of Ireland has all available records.
Claudius Ptolemy or in Latin, Claudius Ptolemaeus, lived about 100 AD to about 170 AD and was a Greek mathematician, astronomer, geographer, and astrologer. He lived in the city of Alexandria in Egypt. Ptolemy's Almagest is the only surviving comprehensive ancient treatise on astronomy. Because of its reputation, it was widely sought and was translated into Latin and later European languages.
Ptolemy's model, like all those of his time, was geocentric and was universally accepted until the appearance of simpler heliocentric models by Copernicus around 1500 AD.
Ptolemy's other main work is his Geography, a compilation of geographical coordinates of the part of the world known during his time. The coordinates that he used in his Geographia showed that he knew the earth was a sphere, but he misjudged the circumfrance of it by about 16% too small. No complete copy of his Geographia survives, but there are several fragments extant, the best of which is in the The Vatican Archives