From the early skirmishes with neighbouring populations under the Roman Kingdom up until the complete conquest of the Italian peninsula, the territorial expansion of Rome required the constant organisation of its dominions and the management of relations with vanquished cities or allied communities.
For centuries, colonies were the most effective system of fulfilling such requirements. Entirely different from the colonies of Magna Graecia or the Phoenicians, Rome’s colonies fell into two major categories. One kind were the coloniae civium Romanorum, or maritimae, made up of a fixed number of Roman citizens (usually 300) despatched as a military outpost to control a territory or stretch of coastline (the first such colonies were Ostia and Anzio but other colonies along these lines continued to be founded up until the end of the Second Century BCE). Another kind were known as coloniae latinae and were made up of mixed communities that could be considerably more numerous, with their own laws with a degree of sovereignty. They still had military obligations and ties with Rome in their dealings with others (Cora and Signia, in Latium, were the first of this kind). Latin colonies were founded both in Italy and in the new Mediterranean territories in great numbers throughout the Republican Age up to the First Century BCE. The most prominent figures of the time embarked on intensely colonialistic policies conceived around the veterans of the civil wars, beginning with Marius and Sulla up until Caesar and Augustus.
Particularly during the Social War, many colonies and communities of socii – independent allies bound to Rome by a treaty (foedus) – were promoted to the rank of municipalities. Rome had already experimented with this juridical status in the subjugation of Tusculum in 381 BCE. In its full implementation, albeit with exceptions and limitations, it ensured the highest possible level of integration with the city, imitating its administrative structure whilst retaining a certain level of autonomy. Such a system was essential for a state whose territorial expanse had long reached considerable proportions.