Religious Successors of Rome

For centuries, the Roman Empire dominated what they called mare nostrum, meaning “our sea.” It was through networks of exchange in the Mediterranean Sea that the Roman way of life spread and flourished. Those alive at the time likely believed the huge empire would last forever. No one expected it would split into competing and hostile parts divided by politics and religion. But over time the prosperity and stability of the empire became a thing of the past.

After the split of the empire by the fifth century, three principal successors to its vast territory emerged. Each of these societies eventually would take Rome’s place by restoring political and social order in new ways. They defined themselves differently than the old Roman world and based their communities largely on religion. One successor of Rome was Islam, whose followers established a caliphate that would eventually conquer a large portion of formerly Roman territory. The other two were the Byzantine Empire (or Byzantine Christendom) in the east and a number of states practicing Roman Catholicism (or Latin Christendom) in the west.

The communities of Byzantium and Latin Christendom shared a common bond of Christian faith, and we sometimes collectively call them “Christendom.” The communities of Western Europe in this period are generally known as Latin Christendom. The eastern region of Europe formed a Christian state around the city of Byzantium (Constantinople). It was still similar enough the Roman Empire that people living under Byzantine rule would have proudly called themselves Romans. The Christian faith thus became a binding link, or network, for the entire region.

People could travel and trade across this vast region and still share commonalities with each other even though they may not have spoken the same language.

Yet, although Latin Christendom and the Empire of Byzantium shared one Christian faith, they developed different ways of thinking and living. Each emerged from the destruction, chaos, and cultural decline of the Roman empire and developed their own intellectual and institutional traditions. These traditions then become part of their faith and shaped their communities in quite different ways.

Byzantium and the beginnings of religious schism

Byzantium, unlike Latin Christendom, remained one unified empire during most of this period. One of the most important early rulers of Byzantium was Justinian (r. 527-565 CE) who was born to peasant parents but, with help of his uncle, became emperor. Justinian’s wife, Theodora, was his most important advisor. Together, they made sure the emperor was at the center of both state and religious developments. His goal, therefore, was for the emperor to control all aspects of the state and the church.

As time went on, religious differences emerged between the Byzantine practice of Christianity and that of Latin Christendom, to the west. One of the most important internal disputes between the church in the east with those in the west revolved around the divine nature of Jesus. The eastern church believed that Jesus was the son of God and therefore of two natures—one divine and one human. The western church believed that Jesus was the son of God but that both had existed for all of eternity and therefore their divinity was co-equal. Justinian called a council of church leaders together to try and work out these differences but neither side was willing to budge. But this was not the only difference between the east and the west. There were divisions based on language (east = Greek; west = Latin); celibacy (east = married priests; west = celibate priests); and bread used for Eucharist (east = leavened bread; west = unleavened).

In the eighth century there would also be a rift about icons, or religious/artistic images of Christ, Mary, and the saints. This rift became known as the iconoclasm controversy. In Byzantium, the emperor Leo III (r. 717-741 CE) banned imagery depicting Christ or the blessed Mary, and all pictures and statues of faith were smashed. For a community bound by their religious faith, these images meant everything. And it wasn’t like you could scroll back on your social media feed to remember what something looked like. At a time when many were not literate, these icons represented links to the divine and a tool to understand important Biblical stories. In essence, the icons allowed people from all social classes to understand and participate in the faith, which helped to create a sense of community among believers. The ban was eventually lifted but not until the mid-ninth century. By that time iconoclasm created even more tension between the churches of the east and west.

Latin Christendom as a new community

In the eighth century (c. 700 CE), a new warrior dynasty arose, gained control, and nearly re-created the entire old Roman empire in Western Europe. This ruling family, the Carolingians, were a mix of Germanic culture and Christian faith. Unlike the Byzantine empire, the Christian rulers in Western Europe did not dominate religious doctrine. That was the pope’s job. On Christmas Day in the year 800 CE, Pope Leo III (r. 795-816 CE) flexed his authority by crowning the Carolingian ruler Charlemagne “emperor of the Romans.” This affirmed the papal authority to crown emperors and declared a firm separation from Byzantine control. Between the crowning of Charlemagne as Holy Roman Emperor and the iconoclasm controversy, tensions between the west and east were nearing a breaking point.

By the eleventh century, Latin Christendom was experiencing a new wave of religious enthusiasm. Churches sprang up across the medieval landscape and people would travel great distances to visit shrines dedicated to Christian saints. The quest for personal salvation drew many pilgrims to these shrines which held remains and relics connected to the saints’ lives.

However, this religious passion also endangered religious minority groups outside the faith of Latin Christendom. Sporadic yet widespread anti-Semitic violence threatened minority Jewish groups within Latin Christendom. What began as peaceful pilgrimages would eventually evolve into armed crusades against “enemies of Christ”—and these enemies often included Jews, Muslims, and even members of the Byzantine church. These crusades united the communities of Latin Christendom against what was perceived as a common enemy. The goal was to reclaim the Holy Land (Jerusalem) from the Muslims, but the crusaders often persecuted Jews and other minority groups as well.

The Byzantium and Latin Christendom network splits

By the eleventh century, Byzantine and Latin forms of Christianity were quite different, and both sides were taking actions to prevent what they believed to be the incorrect or heretical doctrine of the other one from spreading. The pope began closing churches in Italy that were aligned with the eastern faith. The Byzantine patriarch responded in kind by closing Latin churches in the empire. At the end of all of this back and forth, the pope decided to excommunicate the patriarch from the church, and of course, the patriarch did the same to the pope. Sounds a bit like the old schoolyard taunt: “I’m rubber and you’re glue; whatever you say bounces off of me and sticks to you.”

The two sides could no longer exist together, and in 1054 CE they officially broke apart in what is known as the Great Schism. The break-up would lead to the separate (but still both Christian) faiths of Roman Catholicism and Eastern Orthodox. The break, however, was not entirely complete. Nearly 40 years after the official schism, the Byzantine empire would request the Catholic Church’s help in defeating the Muslims, who were threatening to invade Constantinople.

The Crusades were actively promoted by both popes and patriarchs, emperors and kings. These holy wars dominated much of the twelfth and thirteenth centuries and grew from the popular religious enthusiasm of Latin Christians. In response, thousands of ordinary people from all over Latin Christendom walked over 2,000 miles through Europe and the Byzantine empire to reach the Holy Land, while others traveled overseas. All went as part of a military pilgrimage driven by religious enthusiasm and the promise of new land. This campaign was remarkably successful in uniting Latin Christendom and even mending the rift between eastern and western Christianity for a time, but the truce didn’t last very long. By the fourth Crusade, Latin crusaders, supposedly on a campaign against Muslim opponents, sacked the Christian city of Constantinople instead.