The document discusses the history and spread of civilization in Eastern Europe from the Byzantine Empire through the emergence of Kievan Rus. It details the origins and achievements of the Byzantine Empire under Justinian, including reconquests in Italy, building projects like Hagia Sophia, and legal codification. It then covers the influence of the Byzantine Empire and spread of Orthodox Christianity among Slavic peoples through missionaries like Cyril and Methodius. Finally, it summarizes the rise of Kievan Rus centered around Kiev, its conversion to Orthodox Christianity under Vladimir I, and cultural influences from Byzantium before its decline due to succession struggles and invasion by Asian conquerors like the Mongols.