The Empire of Byzantium was the eastern portion of the Roman Empire, which was divided in 395 A.D. Its capital of Constantinople, located on a peninsula, was naturally secure from invasion on three sides, and its fourth side was fortified with a network of three walls that withstood direct attack for over a thousand years. Its stable economy provided a strong military and, together with an abundant food supply and advanced civil engineering, a high standard of living. Christianity was firmly entrenched in Byzantium, and literacy was more widespread than in any other nation in the middle ages. Although the predominant language was Greek, Latin was also fairly common, and at one point all seventy-two of the world's known languages were represented in Constantinople. Intellectual and artistic endeavors thrived.
...Its rich historiographical tradition (strongly influenced by the church) preserved ancient knowledge upon which splendid art, architecture, literature and technological achievements were built. It is not an altogether unfounded assumption that the Renaissance could not have flourished were it not for the groundwork laid in Byzantium.
Nothing like it was ever built before or after. Construction work lasted five years [532-537] and on December 27, 537, Patriarch Menas consecrated the magnificent church.