The fall of the Roman Empire in the fifth century C.E. is widely held to mark the beginning of the Medieval Period or the middle ages. the Medieval Period lasted for about one thousand years in Italy and somewhat longer in northern Europe.
At the beginning of the Middle Ages Christianity was firmly in place in Italy, and the remnants of the Roman Empire. The farther away from Rome that people lived the more likely it was that they still followed local customs and religions which predated Christianity.
By the end of the Medieval Period, and the beginning of the Renaissance, Christianity was the norm throughout Europe. There were, or course, people following Judaism and Islam, but the majority throughout Europe were Christian. In western Europe the Roman Catholic Church predominated and the Byzantine or Eastern Orthodox Church held sway in eastern Europe and parts of Asia.
During the Middle Ages the clergy, from the Pope to the local priests gained increasing power over the lives of all the people, and became increasingly political. The Pope and the Church hierarchy took an active part in governing countries, kingdoms, and city-states.
Between 1096 and 1291 the Crusades took place. There were four major Crusades and a number of smaller crusades. The first Crusade started as a result of Pope Urban II calling for his followers to recapture the Holy Land from the control of the Moslems.
The Crusades resulted in several changes in the religious life of people over the course of 200 years. At the start, the Crusades increased the power of the Catholic Church since the Pope had originally called for it to begin. Ultimately the Crusades were a failure because the Holy Land was still not under Christian control 200 years later. That failure led to a lot of disillusionment with the institution of the church but not religious beliefs.
Prior to the Crusades the people were tied to the land in that most people lived their entire lives in the place where they were born. After leaving to go Crusading, many chose not to return.
The cities which had been the jumping off points for the Crusades became centers of trade from all places in the known world and they continued to be, after the Crusades ended.
Commerce and trade continued to increase in Europe and lead to the beginning of a Merchant Class that was no longer dependent on the Feudal masters for their livelihood and so were also not as dependent on the church.
These changes in part pointed the way toward the Renaissance.