Such was the country that was then ruled by the royal Piasten families under the Polish sovereignty, which, however, was often disputed, and sometimes entirely thrown off. A great dissimilarity might however be discerned in the different branches of the family. The Piastens of Upper Silesia united themselves closely with Poland, and kept up the Sclave habits in their country, so that even at the present day a Sclave population is to be found there; but the rulers of Lower Silesia adhered to the Germans. It was their policy to marry the daughters of the German princes: they set the highest value upon everything German, and German manners were introduced into the court; their children were sent to travel in Germany, and often brought up there, so that in the beginning of the thirteenth century, the Piasten family was held in great consideration throughout that country; they sought for knighthood from their relations in the west, and out of courtesy to them dressed their followers in their colours. They knighted their own nobles with the German straight sword, instead of using the crooked Sclave sabre; they preferred getting drunk on malmsey and Rhine wines, instead of the old mead. The German dances were in great request among the ladies of the court. In this way a numerous German nobility was established in the country, for these courtiers or adventurers and their relations soon became landed proprietors, and the Sclavonian institution of the Castellan was replaced by the German feudal tenure. But an influx of priests and monks tended still more to the promotion of German habits; a stream of them poured incessantly from the west into the half-civilized country. Monasteries, cloisters, and other pious establishments sprang up rapidly, and became as it were the strongholds of German life; for the brotherhoods of the west sent their best and most distinguished members, and continued to furnish them with learning, books, and spiritual energy. The princes, nobles, and clergy soon became aware of the difference between German and Sclave labour; under the latter, large tracts of country yielded little produce, except wood from the forest and honey from the heath. The landed proprietors therefore, with due regard to their own interests, introduced everywhere German labour. Thus in Silesia the great truth first dawned upon men, on which rests the whole system of modern life, that the labour of free men, can alone give stability to a nation and make it powerful and prosperous. The landed proprietors gave up the greater part of the claims which, according to the Polish law, they had upon men who dwelt on their property, and which were so exorbitant that they derived but little benefit from them. The princes granted the inhabitants as a favour, the right of founding cities and villages in accordance with German law, that is to say, free communities, and this privilege was eagerly sought after, especially by the ecclesiastical bodies, such as Cistertians,