There are two controlling reasons, one internal, the other external. The external reason is to be found in this, that slave hunting on a profitable scale is scarcely possible at this time in any part of the world, since nearly all countries within reach are also organized as strong states. Wherever it is possible, as for instance, in the American colonies of the West European powers, it develops at once. The external reason may be found in the circumstance that the peasant of the interior countries, in contrast to the conditions prevailing in the maritime states, is subject, not to one master, but to at least two[V] persons entitled to his service, his prince and his landlord. Both resist any attempt to diminish their peasants’ capacity for service, since this is essential to their interests. Especially strong princes did much for their peasants, e. g., those of Brandenburg-Prussia. For this reason, the peasants, although exploited miserably, yet retained their personal liberty and their standing as subjects endowed with personal rights in all states where the feudal system had been fully developed when the system of payments in money replaced that of payments in kind. [V] In mediæval Germany the peasants pay tribute in many cases not only to the landlord and to the territorial prince, but also to the provost and to the bailiff. The evidence that this explanation is correct may be found in the relations of those states which were gripped by the system of exchange in money, before the feudal system had become worked out. This applies especially to those districts of Germany formerly occupied by Slavs, but particularly to _Poland_. In these districts, the feudal system had not yet been worked out as thoroughly as in the regions where the demand for grain products in the great western industrial centers had changed the nobles, the subjects of public law, into the owners of a _Rittergut_,[W] the subjects of private economic interests. In these districts, the peasants were subject to the duty of rendering service only to _one_ master, who was both their liege lord and landlord; and because of that, there came into being the republics of nobles mentioned above, which, as far as the pressure of their more progressed neighbors would permit, tended to approach the capitalistic system of exploiting of slave labor.[140] [W] See foot-note on page 84.