The first valuable contribution the Greeks made to political study was that they invented it. It is not too much to say that, before fifth-century Greece, politics did not exist. Rameses and Nebuchadnezzar, Croesus the Lydian and Cyrus the Persian, ruled over great empires; but within their dominions there were no politics because there were no public affairs. There were only the private affairs of the sovereign and his ruling class. Government and all that pertained to it, from military service and taxation to the supply of women for the royal harem, was simply the expression of the power and desire of the ruler. The great advance made by Greece was to have recognized that public or common interests exist and to have provided, first for their management, and secondly for their study.