Moving with his family from outpost to outpost, the memories of his old home would grow blurred, and the legion to which he belonged would occupy the chief place in his thoughts. As he grew older his sons, bred in the atmosphere of war, would enlist in their turn, and so the military profession would tend to become a caste, handed down from father to son. The soldier could have little sympathy with fellow citizens whose interests he did not share, but would despise them because they did not know how to use arms. The civilians, on their side, would think the soldier rough and ignorant, and forget how much they were dependent on his protection for their trade and pleasure. Instead of trying to bridge this gulf, the government, in their terror of losing taxpayers, widened it by refusing to let _curiales_ enlist. At the same time they filled up the gaps in the legions with corps of Franks, Germans, or Goths; because they were good fighting material, and others of their tribe had proved brave and loyal. In the same way, when land in Italy fell out of cultivation, the Emperor would send numbers of barbarians as _coloni_ or settlers to till the fields and build themselves homes. At first they might be looked on with suspicion by their neighbours, but gradually they would intermarry and their sons adopt Roman habits, until in time their descendants would sit in municipal councils, and even rise to become Praetors or Consuls. [Sidenote: Barbarian Invasions] When it is said that the Roman Empire fell because of the inroads of barbarians, the impression sometimes left on people’s minds is that hordes of uncivilized tribes, filled with contempt for Rome’s luxury and corruption, suddenly swept across the Alps in the fifth century, laying waste the whole of North Italy. This is far from the truth. The peaceful invasion of the Empire by barbarians, whether as slaves, traders, soldiers, or colonists, was a continuous movement from early imperial days. There is no doubt that, as it increased, it weakened the Roman power of resistance to the actually hostile raids along the frontiers that began in the second and third centuries and culminated in the collapse of the imperial government in the West in the fifth. An army partly composed of half-civilized barbarian troops could not prove so trustworthy as the well-disciplined and seasoned Romans of an earlier age; for the foreign element was liable in some gust of passion to join forces with those of its own blood against its oath of allegiance.