Mag Breg

The Kings of Brega were rulers of Brega, a petty kingdom north of Dublin in medieval Ireland.

Brega took its name from Magh Breagh (Breá), meaning "fine plain", in modern County Meath, County Louth and County Dublin, Ireland. They formed part of the Uí Néill kindred, belonging to the Síl nÁedo Sláine branch of the southern Uí Néill. The kingdom of Brega included the Hill of Tara, the site where the High King of Ireland was proclaimed. Brega was bounded on the east by the Irish Sea and on the south by the River Liffey. It extended northwards across the River Boyne to the foothills of County Louth. The western boundary, which separated it from the Kingdom of Mide, was probably quite fluid and is not accurately known.

Brega was annexed in the 6th century by the Uí Néill. By the middle of the 8th century the Síl nÁedo Sláine had split into two hostile branches: Southern Brega, or the Kingdom of Loch Gabhair, which was ruled by the Uí Chernaig; and Northern Brega, or the Kingdom of Cnogba/Knowth, which was ruled by the Uí Chonaing. Despite this, many kings of Brega ruled over both areas, and thus Brega as a whole, until the kingdom's extinction in the early years of the Norman invasion of Ireland.

List incomplete: see Mac Shamhráin, 2004. The Uí Chonaing had earlier been settled around Tailtiu and Ráith Airthir in the valley of the Blackwater; that district was left to another branch of Síl nÁeda Sláne, Síl nDlúthaig upon the conquest of the Ciannachta Breg during the reign of Cináed mac Írgalaig. The title King of Ciannachta is first used by this dynasty in the Annals of Ulster in the year 742 and the use of the title King of Cnogba in 818; prior to this, it was a title used by the Ciannachta themselves. Earlier kings can be considered chiefs of the Uí Chonaing.

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