The low political vitality of the three primitive Roman tribes, as of the corresponding Greek phylae,[22] when we first meet with them in history, points to the artificiality of these groups—a condition indicated further both by their number and by their occurrence in other Italian states.[23] Far from being confined to Rome, the tripartite division of the community belonged to many Greek and to most Italian peoples,[24] and has entered largely into the organization of communities and nations the world over.[25] A derivation of tribus, Umbrian trifu, accepted by many scholars, connects it with the number three.[26] The wide use of this conventional number, and more particularly the regular recurrence of the same three Dorian tribes in many Dorian cities—as of the same four Ionic tribes in many Ionic cities[27]—and of the same three Latin (or Etruscan?) tribes in several old Latin cities, could not result from chance combinations in all these places, but point unmistakably to the systematic imitation of a common pattern. That pattern must be ultimately sought in the pre-urban populus, ἔθνος, folk. If we assume that before the rise of city-states the Ionian folk was organized in four tribes (phylae) and the Dorian and Latin folks in three tribes, we shall have a condition such as will satisfactorily explain the tribal organization of the city-states which grew up within the areas occupied by these three folks respectively. The thirty votes of the Latins may be best explained by assuming a division of their populus into three tribes, subdivided each into ten groups corresponding to the Roman curiae. Whereas in Umbria the decay of the pre-urban populus allowed its tribes to become independent,[28] in Latium a development in that direction was prevented by the rise of city-states, which completely overshadowed the preëxisting organization. The Italian city-state grew not from a tribe or a combination of tribes, but from the pagus,[29] “canton,” a district of the pre-urban populus with definite consecrated boundaries,[30] usually centering in an oppidum—a place of defence and refuge.[31] In the beginning the latter enjoyed no superior right over the territory in which it was situated.[32] A pagus became a populus at the point of time when it asserted its political independence of the folk. The new state organized itself in tribes and curiae after the pattern of the folk. In the main this arrangement was artificial, yet it must have taken some account of existing ties of blood.[33] At the same time the oppidum became an urbs[34]—a city, the seat of government of the new populus. Thus arose the city-state. In the case of Rome several oppida with parts of their respective pagi[35] were merged in one urbs—that known as the city of the four regions.[36] Urbs and ager excluded each other, just as the oppidani contrasted with the pagani;[37] but both were included in the populus.