拜占庭帝国(Byzantine Empire)
位於欧洲东南方和南方及亚洲西部的帝国。「拜占庭」一词，源於古代希腊在博斯普鲁斯海峡岸边的一个殖民地名称。西元330年罗马皇帝君士坦丁一世接管这里，易名为君士坦丁堡（伊斯坦堡）。此时该地区通称东罗马帝国。395年君士坦丁去世後，狄奥多西一世将帝国分给两个儿子。476年西罗马帝国灭亡，东半部的罗马帝国延续下来，成为拜占庭帝国，以君士坦丁堡为其首都。东部地区在许多方面有别於西半部：它继承了希腊化时代（Hellenistic Age）的文明，因此人口稠密，商业繁荣。在它最伟大的皇帝查士丁尼一世（527～565年在位）掌权後，重新征服了一些西欧地区，兴建圣索菲亚教堂，并公布了以罗马法律为基础的法典。他死後，帝国逐渐衰落。虽然在查士丁尼死後许久，其统治者仍以「罗马」自居，但「拜占庭」则更能适切的形容这个中世纪帝国。长时期因破坏圣像主张的争论，使得东方教会和罗马教会决裂（参阅Schism of 1054）。在东西方教会相对抗时期，阿拉伯和塞尔柱土耳其人在这个地区加强他们的力量。11世纪晚期，亚历克赛一世.康尼努斯向威尼斯和罗马教宗寻求协助，随着这个结盟继之而来的是十字军的掠夺。在第四次十字军东征时，威尼斯人占领了君士坦丁堡，并拥立另一支的拉丁皇帝。1261年拜占庭重新复国，但领土大为缩小，像是一个以君士坦丁堡为中心的城邦国家。14世纪鄂图曼土耳其开始入侵，1453年最後一位皇帝在奋战後丧命，土耳其人占领君士坦丁堡，从而结束了拜占庭帝国。
English version：
Byzantine Empire
Empire, southeastern and southern Europe and western Asia. It began as the city of Byzantium, which had grown from an ancient Greek colony founded on the European side of the Bosporus. The city was taken in AD 330 by Constantine I, who refounded it as Constantinople. The area at this time was generally termed the Eastern Roman empire. On the death of Constantine in 395, Theodosius I divided the empire between his two sons. The fall of Rome in 476 ended the western half of the Roman empire; the eastern half continued as the Byzantine empire, with Constantinople as its capital. The eastern realm differed from the west in many respects: heir to the civilization of the Hellenistic era, it was more commercial and more urban. Its greatest emperor, Justinian (r. 527-565), reconquered some of western Europe, built the Hagia Sophia, and issued the basic codification of Roman law. After his death, the empire weakened. Though its rulers continued to style themselves “Roman” long after Justinian's death, the term “Byzantine” more accurately describes the medieval empire. The long controversy over iconoclasm within the Eastern Church prepared it for the break with the Roman Church (see Schism of 1054). During the controversy, Arabs and Seljuq Turks increased their power in the area. In the late 11th century, Alexius I Comnenus sought help from Venice and the Pope; these allies turned the ensuing Crusades into plundering expeditions. In the Fourth Crusade the Venetians took over Constantinople and established a line of Latin emperors. Recaptured by Byzantine exiles in 1261, the empire was now little more than a large city-state. In the 14th century the Ottoman Turks began to encroach; their extended siege of Constantinople ended in 1453, when the last emperor died fighting on the city walls and the area came under Ottoman control.