The political development that our part of the world has undergone in later times, and the result of which is the modern European political system, is characterised principally by two circumstances. On the one hand, the nations feel themselves more and more real unities; they do not suffer themselves to be divided, or sold, or exchanged, as easily as before. The idea of nationality has forced its way strongly, and has demanded recognition with great persistency. This demand of the different nations for national independence, more clearly understood and more and more consciously realised in the process of time, need not, however, bring with it an isolation of the peoples from each other. For just as little as the individual without danger to the development of his life can shut himself out from communication with others, so such a thing is as little possible for nations. Besides the tendency now alluded to, and quite as strong, there is another whose aim is to join the nations with each other, and which makes itself felt in livelier intercommunication and a more intimate culture-connection between the peoples. No really important event in the life of one nation can come to pass without having a certain influence on that of the others. ‘There is,’ says Ranke, ‘no country's history in which universal history does not play a great part.’ This is of course especially applicable to the great events which have made historical eras.