The general outlines of the Norman settlement of Leinster were laid downin the time of Strongbow. At the time of the Norman invasion that part of Leinster which was to become Kildare was divided into four main tribal territories, described as cantreds under the Normans: Offelan in the north; Offaly to the north-west and centre; Omurethy in the south; and Leix to the south-west.

Offelan is now represented by the baronies of North and South Salt, Ikeathy and Oughterany, and Clane (formerly Otymy), which were granted to Adam de Hereford, who shared his grant with his brothers John and Richard; and North and South Naas, which were granted to Maurice Fitz Gerald, whose son, William, also divided his grant with his brother Gerald, the ancestor of the earls of Kildare.