In Central Europe the Slavs may be said in a certain sense to have retreated, for in former times they occupied the whole of Northern Germany as far as the Elbe.

But what does the word "retreat" mean in this case?
It means probably that the Slays were gradually Teutonised, and then absorbed by the Teutonic race.

Some tribes, it is true, swept over a part of Europe in genuine nomadic fashion, and endeavoured perhaps to expel or exterminate the actual possessors of the soil.

This kind of migration may likewise be studied in Russia.

But I must leave the subject till I come to speak of the southern provinces..