_Secondly_, conquest was not the work of a single day; it continued to be carried on after the establishment of the invaders. All the documents of the period indicate that the principal officers and large proprietors continually exerted themselves, either to usurp the possessions of their less powerful neighbours, or to impose upon them rentals or other charges. These usurpations are proved by the multitude of laws that were enacted to prevent it. In the unsettled state of society that then existed, the feeble were entirely placed at the disposal of the strong; public authority had become incompetent for their protection; many lands which were at first free, and belonged either to their ancient owners, or to Barbarians of slender resources, fell into a tributary state; many of the smaller proprietors purchased for themselves the protection of the strong, by voluntarily placing their lands in this condition. The most common method of rendering lands tributary, was to give them either to churches or to powerful proprietors, and then to receive them again, on the tenure of usufruct, to be enjoyed during life, on the payment of fixed fees. This kind of contract is to be met with again and again, during this period. The same causes which tended to destroy allods, or to convert them into benefices, acted with even more energy in augmenting the number of tributary lands.
_Thirdly_, many large proprietors, whether of allodial lands or of benefices, were unable themselves to cultivate the whole of their lands, and gave them up by small portions to simple cultivators, on the payment of certain fees and services. This alienation took place under a multitude of forms and a variety of circumstances; it certainly occasioned many lands to become tributary. The large number and endless variety of rentals and rights, known in a later time by the name of _feudal_, arose probably either from similar contracts, or from usurpations committed by the powerful proprietors. The constant recurrence in writers and laws of the period of the terms _census_ and _tributum_; the multitude of arrangements which relate to them; the general course of events; lastly, the state in which most landed property was found when order began to reappear,--all these circumstances render it probable that at the end of the period we are considering, the greater number of lands had fallen into a tributary condition. Property and liberty were alike devoted to be plundered. Individuals were so isolated, and their forces so unequal, that nothing could prevent the results of such a position.