The Byzantine Empire is the first great Empire during the Middle Ages, but it was nothing more than the Eastern Roman Empire, in other words, the direct continuation of the Ancient Roman Empire more with some differences as the Greek language as predominant in contrast to the Latin language the Roman West and also characterized by a Christian church in the empire State.
The distinction between the Roman Empire and the Byzantine Empire is a modern convention, it is not possible to assign a date of separation, but an important point is to transfer the current capital of the Eastern Roman Empire Nicomedia to Byzantium in 324 by Constantine I. Byzantium became Constantinople, which means "city of Constantine", which today is the city of Istanbul.
The Roman Empire was finally divided in 395, after the death of emperor Theodosius I, becoming completely separated from the West, and being spared the difficulties faced by the West until its fall in 476.
The first emperor was Arcadius, son of Theodosius I to rule the Byzantine Empire. But it was his son Theodosius II strengthened the walls of Constantinople, building the Wall of Theodosius between the years 408-412 leaving you immune to most attacks city, not being violated until 1,204.
During the Byzantine empire that lasted over 1,000 years there were several dynasties, each with its pinnacles and falls. But for most of its existence, it remained the most powerful military, economic and cultural force in Europe, despite setbacks and territorial losses, especially during the wars against the Persians and Arabs.
In the religious field the official church of the Byzantine Empire was the Orthodox Church which has a common history with the Roman Catholic Church until the eleventh century, when in 1,054 there was a break between the Catholic West and the Orthodox Church in the East has been called Schism East. The deterioration of relations between the two churches has largely contributed to the episode of the sack of Constantinople during the Fourth Crusade in 1,204 , when it was dissolved and divided into competing Latin and Greek kingdoms, being restored in 1,261.
However successive civil wars in the fourteenth century further sapped the strength of the weakened empire, and most of the remaining territories were lost in the Byzantine-Ottoman Wars, which culminated in the Fall of Constantinople and the conquest of remaining territories by the Ottoman Empire in the fifteenth century.
After the conquest of Constantinople was the migration of Byzantine intellectuals who took with knowledge that influenced the cultural movement known as the Renaissance and the spice trade, previously monopolized by Venice and Genoa, were shaken, as besides being charged high rates for marketed products was very dangerous for Christians to navigate these sides of the Mediterranean. That was one of the reasons that led the nation states began to search for new routes to get the spices of India and China. It was after the fall of Constantinople to Portugal discovered the sea route to India, and Spain, Christopher Columbus arrived in America. As a consequence the republics of Genoa and Venice went into decline as the Portuguese bypassed Africa and came to India and the Spanish discovered America.
The various economic and political changes that followed the fall of the Byzantine Empire or Eastern Roman Empire led historians to have agreed the year 1,453 as marking the end of the Middle Ages and the end of feudalism in Europe, causing the fall of the Byzantine Empire a major milestone for the discovery of new lands, and the development of capitalism in the world and to the entry of humanity in the modern age.