 Constantinople played a significant role in the Kiev Rus development, culture, and politics.Many of the Kiev Princes were married to daughters of the Byzantine Emperors, and because of this connection Eastern Europe became Orthodox, after it was Christianized by Vladimir the Great of Kiev.However these relationships were not always friendly - Constantinople was sacked several times over those 400 years by Kiev Princes, forcing Constantinople to sign increasingly favorable treaties for Kiev, the texts of which were preserved in the Primary Chronicle and other historical documents (see Rus'-Byzantine Wars).