Description Clare is a maritime county in the province of Munster, bounded on the west by the Atlantic, on the north-west by Galway Bay and on the east and south by the river Shannon. The present county formed, from a very early period, a native principality, Tuath-Mumhan, or Thomond, signifying 'North Munster'. The area was divided into cantreds or baronies, each occupied by their ruling families. The O'Loughlins, O'Garbhs, O'Briens, O'Connors, O'Deas, McMahons and McNamaras were the main clans. Together, these families are generally referred to as the Dalcassian families, from Dal gCais, a name for the eastern half of the county.The O'Briens were a major force in Thomond from earliest times. The Danish Vikings raided this county on many occasions during the 9th and 10th centuries. They were finally defeated at the beginning of the 11th century by the most famous of the O'Briens, Brian Boru, who also led the army which defeated the Danes of Dublin at Clontarf in 1014.Following the Norman invasion, Thomond was granted to Thomas de Clare who attempted to take control of the county but was eventually defeated by the O'Briens. The O'Briens were later made Earls of Thomond and thereby remained the major force in the county for centuries. The county boundaries were established by the English administration in 1565.Following the defeat of the 1641 rebellion of the Catholic Confederacy, Clare was set aside to accommodate the 'delinquent proprietors', i.e. those proprietors whose land was confiscated because they did not actively oppose the rebellion. Parts of the lands of the existing Clare landholders were confiscated to accommodate these landholders.