Byzantine EmpireThe Byzantine Empire, also referred to as the Eastern Roman Empire, was the continuation of the Roman Empire primarily in its eastern provinces during Late Antiquity and the Middle Ages, when its capital city was Constantinople. It survived the fall of the Western Roman Empire in the 5th century AD and continued to exist until the fall of Constantinople to the Ottoman Empire in 1453. During most of its existence, the empire remained the most powerful economic, cultural, and military force in the Mediterranean world.
Walls of ConstantinopleThe Walls of Constantinople (Τείχη της Κωνσταντινουπόλεως) are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul in Turkey) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built.
Ancient Roman architectureAncient Roman architecture adopted the external language of classical Greek architecture for the purposes of the ancient Romans, but was different from Greek buildings, becoming a new architectural style. The two styles are often considered one body of classical architecture. Roman architecture flourished in the Roman Republic and to even a greater extent under the Empire, when the great majority of surviving buildings were constructed.
Hagia SophiaHagia Sophia ( 'Holy Wisdom'; Ayasofya; Hagía Sophía; Sancta Sapientia), officially the Hagia Sophia Mosque (Ayasofya-i Kebir Cami-i Şerifi), is a mosque and a major cultural and historical site in Istanbul, Turkey. The last of three church buildings to be successively erected on the site by the Eastern Roman Empire, it was completed in 537 AD. It was an Orthodox church until the Ottoman conquest of Constantinople in 1453, then a mosque until 1935, then a museum and then from 2020 a mosque again, as well as being a Roman Catholic cathedral for some decades after the Fourth Crusade of 1204.