Schools have the functions of education and academic research, and learn from each other. The most famous education center is also the most powerful academic center. Throughout the Byzantine Empire, there were many centers integrating education and academic research. According to archaeological and documentary evidence, except Constantinople, Athens is the education center of ancient Greek philosophy, language and literature, Alexandria is the center of "all sciences and all kinds of education", Beletus is the center of Latin and legal education, Thessaloniki is the education center of ancient literature and Christian theology, Gaza and Antioch are the education centers of ancient oriental literature and theology, and Ephesus and Nicea are the education centers of Christian theology. The Code of Justinian recorded the "three legal centers" of the Byzantine Empire at that time, namely Constantinople, Rome and Beletus, and stipulated that all government officials, judges and lawyers must obtain relevant academic qualifications before taking up their posts.