The above change, although immediately felt by the German towns, was not realized by them in its full importance either as to its causes or its consequences for more than a century; but the decline of their prosperity was nevertheless sensible, even now, and contributed directly to the coming upheaval.
The impatience of the prince, the prelate, the noble, and the wealthy burgher at the restraints which the system of the Middle Ages placed upon his activity as an individual in the acquisition for his own behoof, and the disposal at his own pleasure, of wealth, regardless of the consequences to his neighbour, found expression, and a powerful lever, in the introduction from Italy of the Roman law in place of the old canon and customary law of Europe.

The latter never regarded the individual as an independent and autonomous entity, but invariably treated him with reference to a group or social body, of which he might be the head or merely a subordinate member; but in any case the filaments of custom and religious duty attached him to a certain humanity outside himself, whether it were a village community, a guild, a township, a province, or the empire.

The idea of a right to individual autonomy in his dealings with men never entered into the mediaeval man's conception.

Hence the mere possession of property was not recognized by mediaeval law as conferring any absolute rights in its holder to its unregulated use, and the basis of the mediaeval notions of property was the association of responsibility and duty with ownership.

In other words, the notion of _trust_ was never completely divorced from that of _possession_.
The Roman law rested on a totally different basis.