Sub-chieftains collected tribute in money and cattle from their own subjects for their overlord, keeping back a proportion for themselves. Fines they imposed for murder or theft might also be shared with the paramount chief. Sub-chiefs with their nobles were bound to attend a popular assembly (oireachtas) held by their overlord once or twice a year, a scene of sporting contests and entertainments for the general public, which also provided the occasion when the chief held council with his leading vassals, proclaimed taxes, or even a future war.
Each chieftainship was hereditary within a particular family. Succession did not necessarily pass to the previous chief's eldest son, but to the kinsman considered most powerful in terms of wealth and followers, the choice being made by a council of nobles, including the ruling kindred, and formally acclaimed by clergy, poets and lesser landowners at the new chief's inauguration ceremony. Unfortunately this means of selecting a Chief sometime led to rival claimants, in the case of the O'Cahans the death of Thomas, with two O'Cahan lords proclaiming themselves "the O'Cahan". The claimants Godfrey, son of Godfrey and grandson of Sean, and the other John, son of Thomas.
Gaelic society was divided into tenants-at-will, freeholders and lords. The tenants-at-will were the tillers of the soil and herders of cattle. They seem to have lived under the jurisdiction of their landlords, without access to the courts of Brehon law, but were also not normally called upon for military service. They probably formed the majority of the population, but many of the freeholders whose landownership brought military obligations as well as legal citizenship, possessed comparatively small farms, representing their share of a larger family estate. Landownership passed from father to sons, but was periodically re-divided among cousins when direct heirs failed, by the senior kinsman (ceann fine). The ceann fine was also responsible for collecting taxes, debts or fines from his kin-group, unless his authority was superseded by that of a patron or lord.
