Ireland was divided into a large number of small districts, each of which was owned by a tribe,[57] the aggregate of a number of clans or families which believed that they were descended from a common ancestor. At the head of the tribe was a “king,” who was elected from a certain family. Below the king were four social grades within the tribe. There were the nobles,[58] who were distinguished by the possession of land. These were the only members of the tribe, besides the king, who had land of their own. After them came those who had wealth in cattle and other movable property,[59] but were only tenants of the land on which they lived. Below these were freemen, who had no property either in soil or in cattle, but farmed lands for which they paid rent. The lowest grade consisted of herds and labourers of various kinds, who were not freemen, but were regarded as members of the tribe and entitled to its protection. There was also another class of slaves who did not belong to the tribe, consisting of strangers—such as fugitives, bought slaves, and captives. Patrick belonged to this class, _fudirs_ as they were called, in the days of his bondage. Originally all the land must have belonged to the tribe. But at the time with which we are concerned, part of the arable land was the private property of the king and the nobles. There were, however, certain restrictions on this proprietorship which show that, theoretically, all the land was still considered as in a certain sense tribal. The chief of these was that the proprietor could not alienate his land without the consent of the tribe. [Sidenote: IRISH TRIBES AND KINGDOMS] The limits of these small tribal kingdoms can be still approximately traced, for they are represented, for the most part, by the baronies of the modern map, and the names of the baronies in many cases preserve the names of the tribes. The inspection of a map on which the baronies are marked will convey a general idea of the number and size of the small kingdoms which formed the political units of the island. These kingdoms varied greatly in size; the tribes varied in numbers and importance. But each kingdom, whether large or small, managed its own affairs. The self-government of the tribes, and the complicated organisation of the clans and families within them, were the most important and fundamental social facts. But the tribal units were grouped together loosely in a political organisation of an elaborate kind, consisting in degrees of overlordship.