The subject matter of the study of politics consists firstly of the groups or collections of men who have lived under governments, and secondly of the governments under which they have lived. In the present chapter I wish to speak of the groups, to describe in outline the various forms which they have taken, and to define the names by which their forms are severally known. I must premise that I shall call some of the groups political communities, meaning by a political community a number of persons living under one government and also having much else in common besides government: the rest I shall call political aggregates, meaning by a political aggregate a number of persons or bodies of persons living under one government and having nothing else or very little else in common. Having said this, I can proceed to notice the forms of individual communities or aggregates, with a view to classifying them according to their forms. In my survey the earliest forms will be taken first, and the others afterwards, as far as possible in chronological order[6]. [6] I have thought it needless in most cases to give authorities for statements of historical facts made in this chapter, because the statements are generally such that it is very easy to settle whether they are true or false. In cases where verification might be in the least degree difficult I have given references. The two European races into whose past we can grope our way farthest back are the Germans and the Greeks. Each of these races, when first we have any knowledge of them, had formed a large number of tribes or small primitive political communities. The German tribes in the times of Cæsar and of Tacitus and the Greek tribes in the time of Homer were alike in being of small size and in being primitive in their habits and government: but in a German tribe the whole population lived scattered over the open country and there was no walled city, while in a Greek tribe, though most of the people lived in the open country, there was a walled city as a centre for the community and a dwelling place for a few of the most important tribesmen. It is desirable to give the word _tribe_ such a definition as will emphasize the distinction between a tribe and a city, and I shall therefore define it as meaning a small primitive political community, living in the open country without any walled city. From this definition it follows that I must regard the German tribes alone as being perfect specimens of the genus tribe or as being tribes pure and simple: the early Greek communities, though for brevity I shall speak of them as tribes, ought in strict accuracy to be regarded as tribes which were on the way to become cities and which had already acquired some small portion of the qualities by which cities are characterized.