The Gaelic political and cultural order of Ireland, organized as a shifting patchwork of tuatha (petty kingdoms) and larger overkingdoms (e.g. Ulaid, Connacht, Munster, Leinster, Mide) under a nominal High King, from the start of the historical record through Christianization, the Viking Age, and the Anglo-Norman invasion.
Progressively supplanted by the Tudor conquest of Ireland; ended symbolically with the 1541-42 'Crown of Ireland Act' and the surrender-and-regrant policy that created the Kingdom of Ireland (already in the dataset), converting Gaelic lords into peers of that new crown kingdom.
The atlas holds 2 border frames for Gaelic Ireland — the shape you scrub through changes in 400 · 600.
Standard modern survey of Gaelic Ireland's political and social order from its earliest historical record through the high medieval period.