Final answer:
Rome's growth was facilitated by its policy of granting citizenship to conquered peoples and allies, which helped to integrate various communities within the empire and expand its military and political influence.
Step-by-step explanation:
The growth of the Roman Empire was partially driven by its flexible approach to citizenship. Unlike Athens, which maintained a more exclusive citizenship policy, Rome strategically granted citizenship to expand its influence and power.
The practice of extending citizenship began early, such as after the 338 BCE victory over the Latin League, when defeated communities were offered limited citizenship without voting rights in exchange for military support and loyalty.
Citizenship in Rome afforded legal protections, political rights, and other privileges, such as the right to run for public office and certain marriage and property rights. It was also a mark of social status.
The criteria to become a citizen and the rights afforded to citizens evolved over time, often influenced by military conquests, alliances, and the needs of the ever-expanding empire. For instance, colonies established by Rome functioned with their own magistrates and assemblies, where colonists enjoyed full Roman citizenship.
Rome’s policy towards foreigners and citizenship was debated and adjusted throughout the empire's history. Critical changes occurred, such as the extension of citizenship to all free residents of the empire in 212 CE.
However, not all were in favor of such inclusive policies. There were instances of resentment toward foreigners, and even among Roman citizens who were seen as outsiders.