During the time the the Roman army was not stop and there was no one to proctect people in those towns or cities.
During Europe Middle ages the civitization are such as lasted from the 5th to the 15th century. It began with the fall of the Western Roman Empire and merged into the Renaissance and the Age of Discovery.
During the time there was a huge difference between being a peasant and being a a serf. Serfswere bound to the land. They were almost like slaves. The people could not be bought and sold, but they could not leave their land without permission.
Religion in the Middle Ages was dominated by Christianity. It is the era in which the great cathedrals of Europe were built and the Catholic Church started its universities in Paris, Tubingen, Cambridge and Oxford. During the Middle Ages, the Catholic Church was the only church in Europe.