The empire's well-defined network of roads and waterways allowed easier travel, while the Pax Romana made it safe to travel from one region to another. The government had encouraged inhabitants, especially those in urban areas, to learn Greek, and the common language allowed ideas to be more easily expressed and understood.[21] Jesus's apostles gained converts in Jewish communities around the Mediterranean Sea,[2] and over 40 Christian communities had been established by 100.[23] Although most of these were in the Roman Empire, notable Christian communities were also established in Armenia, Iran and along the Indian Malabar Coast.[24][25] The new religion was most successful in urban areas, spreading first among slaves and people of low social standing, and then among aristocratic women.[26]