I have said in a former lecture that the "clan system," or, as some prefer to say, the "tribal system," of medieval Ireland, is a modern notion and is an illusion. Its basis is found in the prominence given in Irish literature to the aristocratic kindreds and in the Irish custom of naming territorial divisions by the names of the septs to which their lords belonged. From this has arisen the notion that the sept or clan from whom a territory was named was the people of the territory. The illusion has been enlarged by the loose use of the term "tribe," which quotation has shown applied to a family group consisting of the children, grandchildren and great-grandchildren of one man; the same term being applied to an ancient aristocratic kindred like Dal Cuinn, spread over nearly half of Ireland. Common tenure of land by a family group, necessitating redistribution of the land as new generations come forward, with the use of the term "tribe" to denote such groups, has created the further illusion of a tribal territory held in common and periodically redistributed. These things being illusions, I am reminded that I have not endeavoured to set out the facts in their stead. Let me then take a particular territory like William O'Kelly's kingdom of Ui Maine. In the fifth century, the lordship of this territory, carrying the title of king, was granted by a king of Connacht to his kinsman Maine. His descendants, called Ui Maine, were the principal nobility of the territory in later times. Before Maine, the territory belonged to a Pictish folk, the Sogini or Soghain, also found in other parts of the country. This Pictish folk continued to inhabit the territory under the rule of the sept of Maine, and under the subordinate rule of their own nobles. But even before Maine's time, the population did not consist of a homogeneous tribe of Sogini, for we find record of another folk dwelling there, distinguished from the Picts and classed among the Fir Iboth, _i.e._ the Ebudeans or Hebrideans; and their descendants also remained in occupation, and are named and located in medieval documents. Successive conquests established various degrees of freedom, the measure of freedom being the degree of immunity from tributes and services. Besides these permanent inhabitants, there were landless immigrants who obtained holdings of land on very exacting terms, mitigated, however, by law after long continued occupancy. At the bottom of the scale, there were slaves, who could be bought, sold, or given away. In historical time, the slaves were never numerous.