Within 400 years after Jesus' passion, Christianity developed from an illegal, persecuted, and underground religion into the official, only, and dominating faith of the Roman Empire. Roman Catholicism was the Western expression of that faith.
Schisms and Sects
Catholicism experienced intermittent theological heresies and three major schisms: the Great Schism between east and west, the Great Western Schism of rival papacies, and the Protestant Reformation.
Missions and Expansion
Roman Catholicism spread around the world—first through the Roman Empire, later by Irish missionaries, and still later by European religious orders and lay missioners. Roman Catholicism often built on and incorporated the customs of evangelized peoples via the process of enculturation.
Exploration and Conquest
Before and after Columbus's voyages starting in 1492, Catholicism's expansion was marked not only by growth and innovation, but also sometimes by violence, persecution, and imperialistic tendencies.
Roman Catholicism responded to the Scientific Revolution, Enlightenment, and modernity's push to democracy first by closing its doors to the world, but then by opening its windows.