By the end of the republic the extent of Rome's dominions was every nearly as great as it ever became, and included already the greater part of the known world. This great empire was not, like that of Alexander, the work of a single conqueror, but the result of centuries of warfare and expansion, and its government was therefore not a coherent scheme imposed by a single mind, but an intricate structure embodying the expedients of many successive generations of rulers. Nor can it be said that the political institutions of Rome, though no doubt they helped her to acquire her empire, proved a success as a means of governing it. The city-state constitution broke under the strain imposed on it and had to be replaced by a military monarchy, for the constitution of Rome at the end of the republic, it must be remembered, was still that of a city-state. If the territories which we call the "Roman Empire" can be said to have a constitution at all, it must be described as a kind of federation of city-states of which the sole bond is their common subjection, though in varying degrees, to the supreme city, whose governing organs have to serve the purpose of governing also the whole federation.
In tracing the development of this federation it is best to distinguish three stages, those of the Latin league, the conquest of Italy, and the acquisition of the provinces beyond the seas and beyond the Alps. Not that these stages represent distinct periods; Rome had already conquered several Italian states before she finally suppressed the last revolt of the Latins, and she had acquired provinces overseas before she has finished with Italy, but it was only through her leadership in Latium that she was able to achieve her supremacy over Italy, and at the end of the republic, as well as during the early empire, Italy represented a privileged part of the Roman dominions contrasted with the subject territories beyond her borders.
