Knowledge of historical context is crucial to understanding the New Testament. Alexander the Great, in his conquests, spread Greek culture throughout the Mediterranean world. This would shape the structure of city-states, which would share characteristically Greek institutions, such as the gymnasium and the boule. This would also give rise to religious syncretism, that is, the mixing of different religions. The rise of the Romans would continue this trend of universalization of Greek ideals and religious tolerance, as well as implement the social structure of the Roman household. The Pax Romana, and the vast infrastructures of the Roman Empire, would facilitate the rapid spread of Christianity.