History of Ireland (400–795)

The period includes the Hiberno-Scottish mission of Christianised Ireland to regions of pagan Great Britain and the spread of Irish cultural influence to Continental Europe.

[1] Early Christian Ireland began after the country emerged from a mysterious decline in population and standards of living that archaeological evidence suggests lasted from c. 100 to 300 AD.

During this period, called the Irish Dark Age by Thomas Charles-Edwards, the population was entirely rural and dispersed, with small ringforts the largest centres of human occupation.

Otherwise, kings lived in ringforts larger than the norm, but generally similar; however the possession of luxury objects such as elaborate Celtic brooches was much greater among royalty.

By the early 6th century the church had developed separate dioceses, with bishops as the most senior ecclesiastical figures, but the country was still predominantly pagan.

The monastic movement, headed by abbots, took hold in the mid 6th century, and by 700 Ireland was at least nominally a Christian country, with the church fully part of Irish society.

Eoin MacNeill identified the "oldest certain fact in the political history of Ireland" as the existence in late prehistory of a pentarchy, probably consisting of the cóiceda or "fifths" of the Ulaid (Ulster), the Connachta (Connacht), the Laigin (Leinster), Mumu (Munster) and Mide (Meath), although some accounts discount Mide and split Mumu in two.

Dynastic propaganda claimed this was a traditional division dating back to the 2nd century, but it probably originated in the 8th, at the height of Uí Néill power.