In the fifth century, Rome split into two sections: Western and Eastern. The Western Roman Empire eventually collapsed due to increasing attacks by German invaders .The Eastern Roman Empire, which became known as the Byzantine Empire, did not share that fate and continued to survive well into the 15th century until it fell to the Ottoman Empire in 1453.

The Byzantine Empire was mostly Greek-speaking, with its capital in Constantinople (previously Byzantium). The Empire’s primary religion was Christianity, eventually becoming characterized by Orthodox Christianity, as opposed to Roman Catholic in the West.

667 BC	The city of Byzantium, which would become Constantinople, capital of the Byzantine Empire, was said to be founded by Megarian colonists.
330 AD	Constantine established a new capital, naming it Constantinople, at the existing site Byzantium, a Greek city that was the trade center of the Eastern side of the empire. It was to be the political capital of the empire and would eventually become the capital of the Byzantine Empire.
395 AD	The Roman Empire split in two: the Western Roman Empire with Rome at its center and the Eastern Roman Empire with Constantinople at its center.
476 AD	The Western Roman Empire falls after repeated invasions by Germanic tribes.
526 AD	Justinian rose to power. He was able to conquer some of the lost territory of the former Western Roman Empire, namely the parts of what are modern day Spain, Italy, and Africa. He compiled the laws of the Romans into a single document and constructed the Hagia Sofia.
533 – 554 AD	Justinian I’s generals reconquered Italy and North Africa from the Ostrogoths and Vandals.
568 AD	Lombards conquered Italy. In time they would seize the northern parts from Byzantine influence.
610 AD	Heraclius reigned as Emperor. The Byzantines retook Mesopotamia for a short period. Greek became the primary language of the empire during this time. However, the empire started to decline with the loss of Egypt, Palestine, and Syria to the Arabs.
634 – 641 AD	Arab forces conquered Egypt and the eastern Mediterranean (the Levant). In the next few decades they took North Africa and Sicily.
697 AD	The Byzantine city Carthage (North Africa) fell to an Arabic invasion.
717 – 718 AD	A large Muslim force pressured Constantinople by both sea and land. Fortunately for the Byzantines, they were able to neutralize it.
721 AD	The Byzantines recovered Asia Minor from the Arabs.
726 – 729 AD	Emperor Leo III passed edicts against the worship of images (iconoclasm). This led to a quarrel between the Emperor and his subjects in the Italian Peninsula which eventually broke off from the Empire after a series of armed conflicts.
730 – 787 AD	First Iconoclast Period in which the Emperor encouraged iconoclasm, the worship of religious images as sacred.
800 AD	Pope Leo III in Rome decided to crown the king of the Franks, Charlemagne, as the new emperor of Rome. His decision to do so indicated that the old deference of the church in Rome to Constantinople was gone. This was the first instance since the fall of the Western Empire that there was an emperor of the “west” and the “east.”
813 – 843 AD	Second Iconoclast Period in which Emperor Leo V the Armenian adopted Iconoclasm, possibly after a series of military failures regarded as indicators of divine disfavor.
917 AD	Symeon-led Bulgars overran Thrace.
924 AD	Bulgars tried but failed to invade Constantinople.
941 AD	Prince Igor of Kiev attacked Bithynia and Constantinople. The result of the skirmish was the destruction of the Russian fleet by the Byzantines.
976 AD	Basil II reigned as Emperor.
992 AD	Byzantines granted trading rights for the Venetians.
995 AD	Basil II reconquered Syria from the Arabs.
996 AD	Basil II reconquered Greece from Bulgars.
1014 AD	Basil II defeated Bulgarian forces, earning the title of “Bulgaroktonos,” or “Bulgar Slayer.”
1018 AD	Bulgaria surrendered and became incorporated into the Byzantine Empire. The Danube was restored as the northern imperial frontier.
1054 AD	Christianity at the time divided into the Roman Catholic Church and the Eastern Orthodox Church in what was known as the East-West Schism.
1055 AD	The Normans took over southern Italy.
1071 AD	The Byzantines under Emeror Romanos IV are defeated at Manzikert by Seljuk Turks. This resulted in the Byzantine Empire’s permanent loss of Asia Minor to the Turks. Also, Bari in Italy was conquered by Normans.
1075 AD	Arabs reconquered Syria from the Byzantine Empire.
1087 AD	Byzantines were defeated in Thrace.
1095 AD	Alexius appealed to Urban II at the Council of Piacenza for assistance against the Turks. The First Crusade was planned at the Council of Clermont.
1096 AD	Crusaders arrived in Constantinople. However, they eventually withdrew from cooperating with the Byzantines.
1121 AD	The Byzantines reconquered areas southwest of Asia Minor
1179 AD	The Sultanate of Rum subdued the Byzantine Army at Myriokephalon, ending all hopes of the Byzantines’ hopes of reconquering Asia Minor.
1202 AD	The Fourth Crusade was assembled in Venice.
1204 AD	The Fourth Crusade conquered Constantinople, fragmenting the empire into many Latin states, a Latin empire, and separate Byzantine successor states. This was a blow that the Byzantines never truly recovered from.
1261 AD	Nicaean emperor Michael VIII Palaiologos reconquered Constantinople and restored the Byzantine Empire.
1326 AD	The Asia Minor city, Prusa, was taken by the Ottoman Turks.
1331 AD	Nicaea, the capital city of the Empire within the previous 100 years, fell to the Ottoman Turks.
1341 – 1347 AD	A large-scale civil war and the Black Death tore apart what remained of the Empire. It lost territories to the Ottoman emirate and the Serbian Empire.
1453 AD	The Ottomans overran Constantinople, marking the final destruction of the Roman Empire.
1460 – 1461 AD	The last Byzantine outposts, Empire of Trebizond and Despotate of Morea, fell to the Ottoman Turks.