The Byzantine Empire existed predominantly during the era of Late Antiquity and the Early Middle Ages. Late Antiquity refers to the period roughly from the 3rd century AD to the 7th century AD, characterized by significant political, cultural, and religious transformations in the Roman world. During this time, the Roman Empire underwent profound changes, including the division into the Western Roman Empire and the Eastern Roman Empire (which eventually became the Byzantine Empire).
Following Emperor Diocletian’s division of the Roman Empire in the fourth century AD, the Byzantine Empire arose from the eastern half of the Roman Empire. Generally speaking, the Early Middle Ages ran from the fifth to the tenth century AD, during which time the Byzantine Empire persisted. The fall of Constantinople in 1453 AD marked the end of the medieval era and the shift to the Early Modern Period.