Ireland, protohistory

Ireland can be said to have had a protohistorical period, when, in prehistory, the literate cultures of Greece and Rome began to take notice of it, and a further proto-literate period of ogham epigraphy, before the early historical period began in the 5th century. Attempts have been made to reconstruct the political developments of this period by reference to early medieval Irish genealogical texts.

Early references
Classical writers occasionally refer to Ireland under a variety of names, but these references contain little reliable information. For example, Diodorus Siculus claims that the Prettanoi of the island of Iris eat human flesh. Strabo, who calls the island Ierne, repeats the accusation, adding that they consider it honourable to eat their dead fathers, and openly have sex with their mothers and sisters (although he is dubious about his sources). Pomponius Mela calls it Iuverna and says that, although the climate is unfavourable for grain, grass grows so richly that cattle burst if unrestrained from eating it. Julius Caesar, in his Commentarii de Bello Gallico, is the first to call the island Hibernia, describes it as about half the size of Great Britain, and correctly places it to the west of Britain – unlike Strabo, who places it to the north.

Tacitus
Ireland came closer to Roman thoughts after the conquest of Britain. Gnaeus Julius Agricola, while governor of Britain (AD 78-85), considered conquering Ireland, believing it could be held with one legion plus auxiliaries, and entertained an exiled Irish petty king, thinking to use him as a pretext for conquest. Agricola's biographer and son-in-law Tacitus says that most of the harbours and approaches to the island were known through commerce, but incorrectly places it halfway between Britain and Spain.

Juvenal
The 2nd century poet Juvenal, in his second Satire, contrasting the victories of the Roman army with the low morals of the people at home in Rome, says that, as well as conquering Britain and the Orkney islands, "we have advanced arms beyond the shores of Iuverna". Although Juvenal is not writing history, it is possible that he is referring to a genuine Roman military expedition to Ireland.

Ptolemy
The 2nd century Alexandrian Greek writer Ptolemy, one of the most impotant geographers, mathematicians and astronomers in the ancient world, refers to Ireland in two of his works. In the astronomical treatise known as the Almagest he gives the latitudes of an island he calls Mikra Brettania (Μικρὰ Βρεττανία) or "Little Britain" (the south of the island at 58 degrees, the north at 61 degrees). In his Geography, at the same latitudes, he places the Prettanic island Iwernia, next to its neighbour, the Prettanic island Albion (Britain). The Geography contains the most detailed account of Ireland in classical literature, giving the latitude and longitude of six promontories, fifteen river mouths, ten settlements and nine islands, and naming sixteen population groups.

North coast
Ptolemy describes the northern coast of Ireland, from the Northern Promontory (possibly Bloody Foreland or Rossan Point in County Donegal) in the west, to the Wenniknion promontory (likely Malin Head), the mouth of the river Widwa (likely the Foyle), the mouth of the river Argita (likely the Bann) and the Rhobogdion promontory (Fair Head, County Antrim) in the east. The peoples who inhabit the north coast are the Wenniknioi in the west and the Rhobogdioi in the east.

West coast
The west coast is poorly represented compared to the other three, and identification of the names Ptolemy gives is speculative. He begins with the Northern Promontory (see above), and working north to south names the river Rhawiu (possibly the Erne); the town Magnata (a settlement of the Magnatai people, possibly somewhere in County Mayo); the mouth of the rivers Libniu (possiby Clew Bay), Ausoba (perhaps Galway Bay) Senu (likely the Shannon, although placed too far to the north), Dur (possibly Dingle Bay) and Iernu (possibly the Kenmare), and the Southern Promontory (any one of Slea Head, Bray Head, Dursey Head and Mizen Head). Peoples of this coast are: the Erdinoi near Donegal Bay; the Magnatai or Nagnatai of County Mayo; the Auteinoi between County Galway and the Shannon, identifiable with the early medieval Uaithni; the Ganganoi, also known in north Wales, and the Wellaboroi in the far south-west.

South coast
The south coast stretches from the Southern Promontory to the mouths of the rivers Dabrona (possibly the Lee or the Blackwater) and Birgu (likely the Barrow) and the Sacred Promontory (Carnsore Point, County Wexford). Peoples of the south coast are the Iwernoi in the west, who share their name with the island, Iwernia, and can be identified with the early medieval Érainn; the Usdiai, and the Brigantes in the east, who share their name with a people of Roman Britain.

East coast
From the Sacred Promontory in the south to the Rhobogdion promontory in the north, Ptolemy names the river Modonnu (possibly the Slaney, but more likey the Avoca), the town of Manapia (a settlement of the Manapii), the river Oboka (likely the Liffey; the river Avoca takes its modern name from a misinterpretation of Ptolemy's Oboka), the town of Eblana (a settlement of the Eblanoi, formerly mistakenly identified with Dublin), the river Buwinda (the Boyne), the promontory Isamnion, the river Winderios (possibly Carlingford Lough, Dundrum Bay or Strangford Lough), and the river Logia (Belfast Lough, Loch Laoigh in Irish). Peoples named, from south to north, are: the Koriondoi; the Manapioi, possibly related to the Menapii of Gaul; the Kaukoi, probably not related to the Germanic Chauci of the Low Countries; the Eblanoi; the Woluntioi, identifiable with the early medieval Ulaid; and the Darinoi.

Later references
Roman sources mention raids on Britain by Saxons of north-west Germany, by Picts from Scotland and by two groups of people usually associated with Ireland, the Scotti and the Atacotti. The origins and meanings of Scotti and Atacotti is uncertain. Atacotti disappears with the Romans. Scotti means Gaels to Adomnán in the late seventh century, but not to Columbanus in the early sixth century, who uses the older term Iberi instead. The Scotti are perhaps a confederation of tribes in Ulster, and the Atacotti one in Leinster, but this is not certain.