The Early Period

According to local legends Ireland was inhabited first by various tribes, the most important of which were the Nemedians, Fomorians, Firbolgs, and Tuatha De Danann. These tribes are said to have been eventually subdued by Milesians (Scots). Although Ireland is mentioned under the name of Ierne in a Greek poem of the 5th century bc and by the names of Hibernia and Juverna by various classical writers, little is known with certainty of its inhabitants before the 4th century ad. At that time Irish tribes, called the Scoti, harried the Roman province of Britain. These expeditions were continued and extended to the coast of Gaul until the time of the Loigare, or King MacNeill (reigned 428-63), during whose reign St. Patrick attempted to convert the natives. Although Christianity had been previously introduced in some parts of Ireland, Patrick encountered great obstacles, and the new faith was not fully established in the island until a century after his death (circa 461).

From early times each province of Ireland appears to have had its own king; according to legend these kings were subject to the ardri, or monarch, to whom the central district, called Meath, was allotted, and who usually resided at Tara, a hill in present-day county Meath. Each clan was governed by a chief selected from its most important family. The laws were dispensed by professional jurists called brehons, who were endowed with lands and who were allowed important privileges.

In the 6th century extensive monasteries were founded in Ireland, in which religion and learning were zealously cultivated during the early Middle Ages of Europe. From these establishments numerous missionaries went forth during the succeeding centuries, while many students of distinction from England and the Continent visited Ireland to further their education. The progress of Irish civilisation was checked by the incursions of the Scandinavians, which began toward the close of the 8th century and continued for more than two centuries. The Vikings established settlements on the east coast of Ireland and conducted raids in the interior until their signal overthrow at the Battle of Clontarf, near Dublin, in 1014, by the Irish king Brian Boru.