Among the events of the thirteenth century, the wonderfully rapid colonization of the Sclave country east of the Elbe has never been sufficiently appreciated. In the course of one century a numerous body of German emigrants of all classes, almost as many as now go to America, spread themselves over a large tract of country, established hundreds of cities and villages, and united it for the most part firmly to Germany. Nearly the whole of the eastern part of Prussia extends over a portion of the territory that was thus colonized. The time however of this outpouring of national strength was not the heroic period of Germany. The enthusiasm of the Crusades, the splendour of the Hohenstaufen, the short reign of German chivalry, and the greatest elevation of German art, were at the end of the twelfth and beginning of the thirteenth century, whereas the colonization of the Sclave frontier was carried on with most energy towards the close of it. This was the period when Neumark and Prussia were conquered, and Lausitz, Mecklenburg, Pomerania, Rugen, and Silesia colonized. But there was a striking difference in the case of Silesia; for whilst in the other Sclave countries the people were crushed by the iron hand of the conqueror, and were compelled to adopt German habits of life, Silesia became the centre of a quiet, peaceful colonization, which spread itself far and wide over, the frontier towards the east. How powerful a passion the love of wandering became in the German people at this period, is a point we will not attempt to enter upon. The expeditions of the Hohenstaufens into Italy, and still more the Crusades, had roused and excited the masses, who became restless and eager for foreign adventure; and the life of the peaceful labourer in Germany was full of danger, indeed almost insupportable. Pious monks, enterprising nobles, even princely brides were to be seen knocking at the doors of their peasantry, and trying to induce the young labourers to follow them to Poland. But little is known concerning this emigration; we do not even know from what province the great stream of Silesian wanderers flowed. There are grounds for thinking that most of them came from Magdeburg, Thuringia, and perhaps Franconia. There is no mention of it in the ancient manuscripts or chronicles; the only evidence concerning it might perhaps be found in the Silesian and Thuringian dialects, but even these have not been sufficiently investigated. We have however more knowledge as to who invited the Germans into the country of the Oder. It was the Sclavonian dukes of the Piasten family, who were then rulers of the country.