Spreading the Gospel in the Middle Ages

Although Westerners did not set out to explore the world until the fifteenth century, their beliefs had long since penetrated far and wide. When Constantine the Great and his colleague Licinius had declared Christianity a lawful religion in the Roman Empire in AD 313, they ended almost three centuries of sporadic but sometimes severe persecution. There were many different Christian sects in the fourth century, but the largest and best organised called itself the Catholic (or universal) church and in 392 Theodosius I made Catholic Christianity the official religion of the Empire. The other sects had died out by c.700 and almost all the churches of the medieval world traced their descent from the Catholic church of the fourth century. They accepted the same Biblical books as canonical; their public worship centred on the eucharist, and authority in all of them was vested in bishops. Medieval Christianity in all its forms was deeply influenced by monasticism, a practice that had spread from fourth-century Egypt to all parts of the Christian world, and men and women who lived as religious solitaries were held in particularly high esteem.

The Catholic church, which worshipped in Latin and acknowledged the pope as its senior bishop, was the only institution that survived the collapse of Roman power in the western provinces during the fifth century and the formation of independent kingdoms there by Germanic settlers. By the seventh century all those rulers had been converted to Catholicism, which had also spread beyond the former imperial frontiers to the Celtic lands in Scotland and Ireland. Medieval Western Europe may have been politically fragmented but it remained united in a shared religious faith.