a. The Byzantine Empire acted as a shield against the Arabs and Turks, preventing them from wilder invasions and conquests in Europe. Classical Greek and Roman texts were used during the rule of the Byzantine Empire after the fall of the Roman Empire (in the west). When the Crusades came, the crusaders brought a grand quantity of important Europeans into close contact with the wealthier and sophisticated Byzantine culture. The European texts that were supposedly lost or forgotten were brought back to Europe and this helped start the Renaissance.
~ Civilizations in both halves of Europe managed to move northward
~ The northern political units were less complex and well organized than Mediterranean core civilizations
~ Religion varied; different version of Christianity in the East and West
~There was little commercial connection between the eastern and western Europe, giving them opportunities to develop different ideas from each other
~Eastern Europe was more related to the Roman Empire
~Eastern Europe was more politically advanced than the Western
c. The Orthodox and Catholic churches were originally in the same agenda until they were separated in 1054, mainly over the role of the Pope. The Roman Catholicism follows the pope while Orthodox Christianity does not. Orthodox Christianity follows the Ecumenical Patriarch. Orthodox priests can get married; Catholic priests cannot (Deacons can do so though). A similarity they share is that they both believe in transubstantiation (bread & wine).
d. An emperor, ordained by god, headed the church and state (Chinese political organization). An elaborate bureaucracy supported the imperial authority. The officials could be recruited from all social classes, but aristocrats predominated. They both had carefully military organization, which defended the empire greatly.
e. The decline of the Byzantine empire were mainly due to: the Battle of Manzikert