How did the Romans deal with other religions as their empire expanded?

As the Roman Empire expanded, it generally practiced a policy of religious tolerance, allowing conquered peoples to continue their traditional worship as long as they also honored the Roman gods and the emperor. This approach helped maintain stability and integration within diverse cultures. However, when a religion was seen as a threat to state unity or public order, such as early Christianity, the Romans could resort to persecution. Ultimately, the empire's tolerance waned with the rise of Christianity, which eventually became the official religion.