This weakness went on, gradually increasing, till in the fifth century the country fell an easy prey to the hordes of Barbarians who then poured in upon it. In the fourth century the Visigoths had burst over Southern Gaul, and settled in the fertile plains between the Pyrenees and the Garonne. That part of the country being well peopled and civilised, and the conquerors comparatively small in number, they were in course of time, to a great extent, absorbed into the general population. The civilisation and polity of the Romans thus continued to preserve a comparatively uninterrupted course in the south-west of Gaul. It is a peculiarity of all the Greek and Roman colonies, as compared with those of modern times, that they were established in cities. In the cities were centred all the life and movement of the ancient world. The land of course had to be cultivated, but that was done by bands of slaves led out from the towns. The open country was uninhabited, and except within a short distance from the towns, lay waste and uncultivated. The form of government exercised in the various states, was founded on that of the towns. The supreme power of Rome herself, with all her wide-spread command, was but an extended municipal authority, and every town was in this respect a repetition of the capital on a small scale. As the conquests of Rome extended, this form of government was found inadequate to the control of the numerous nations finally comprised under Roman sway. The Empire, with its stronger grasp and centralised control, with its multitude of functionaries, all appointed by and in constant relation with a central will, alone enabled the existence of Rome to be continued for some centuries. But when the Empire also finally decayed and fell, the old municipal principle again came to the front. As the colonies had been founded in cities, so when the Imperial system gave way, the city again asserted itself; and in Southern Gaul, where the barbarians had been civilised, municipal authority prevailed, and each town became an independent little State--the natural tendency of these municipalities being to detach themselves, and to watch jealously the proceedings of their neighbours. This municipal principle is a leading characteristic of the Middle Ages in Italy and Southern Gaul, and distinguishes these countries from the Northern provinces. Traces of it are still very apparent in Italy and Provence, and contribute greatly to the picturesque character of these provinces. There even yet the soil is to a great extent cultivated by peasants, who dwell together in crumbling old cities perched on the tops of hills, and surrounded with ancient walls. Daily the men, women, and mules descend to their labour in the fields, till the evening, when they may be met toiling up the steep and rocky paths to a well-earned rest in their ancestral town.