Rome's treaty arrangements were varied. Sometimes, even within a single conquered city-state there were multiple arrangements. This was most likely where the aristocrats supported Rome and stood by earlier treaties, while the rest of the people rebelled. Regardless of the type of treaty, all the treaty states had to provide soldiers and give up some of their land to Rome. An extreme case was the Etruscan city of Veii, where the Romans and their allies killed the inhabitants or sold them into slavery, so all the land became Rome's. The land given to Rome by their new allies in these treaties could become public or private, and was sometimes given to the Roman poor, although generally, it fell into the possession of the aristocracy. The Licinian Law of 366 B.C. reflects this tendency of the rich landowners to keep amassing more and more land, since it limited to 500 jugera (a jugerum was about 2530 sq. meters or 5/8 of an acre) the amount of land that a family could own*. In a slightly later period, Roman military leaders rewarded their career soldiers with the land of the conquered.
There were two basic types of treaty arrangements made with the Italic states, civitas 'citizenship' and foedus, which in the plural is foedera (from which word we get federal, meaning 'pertaining to a treaty'). Those accorded citizenship were under Roman law. Whether or not they had the rights of full citizenship depended on the terms of the treaty. It was of this group that some cities could be said to have half-citizenship (municipes) treaties. Whether full or half citizens, the people of these states were considered Romans. The solders they provided were regular Roman soldiers. On the other hand, those states that were socii 'allies' did not live under Roman law, although they were not allowed to have a foreign policy, since only Rome would deal with outsiders. Although they were obliged to furnish troops, their military units were under local, non-"Roman" officers and were smaller. The socii included both Latin and non-Latin allies.
In return for what the allies supplied the Romans, the Romans offered protection against attack.
There was another group with which Rome arranged treaties: its friends (amici) who were not obliged to send troops. Rhodes was one such amicus of Rome.
On page 84 of A Short History of the Roman Republic (1915), one of the many books on Roman history available from the Internet Archive, W.E. Heitland provides an outline of the types of treaties Rome arranged with the Italian cities. An outline based on Heitland's follows.
Civitascives 'citizens' under Roman law
- with full rights
- living in Rome
- living in the ager Romanus 'Roman field'
- living in the citizen colonies, e.g. the faithful of Campania. Such strategic colonies could be on the coasts.
- with private rights only
- living in municipia
- in citizen colonies but as a second class of citizen, e.g., allies who revolted in Campania. Allowed only the private rights: the right to make contracts and the right to contract a legal marriage (commercium & conubium). The "full" citizenship right they lacked was suffragium, the right to vote in the Roman Republic.
- with full rights
Foederasocii 'allies'; ager peregrinus 'foreign field'
Italian allies bound by treaty to provide troops.
- living in old Latin towns
- living in Latin colonies, e.g., Fregellae, Cales. The colonies were normally established inland.
- not Latin, living in treaty states = civitates foederatae
- Geography of Rome
- Latin League
- Veientine Wars
- Battle of Lake Regillus
- Battle of the Allia
- Worst Defeats in Roman History
- Samnite Wars
- King Pyrrhus of Epirus
- Tarentum and the Pyrrhic Wars