Saint Constantine developed the main administrative divisions of what?
Theme (Byzantine district): The themes or themata (Greek: θέματα ; singular θέμα, "thema") were the main administrative divisions of the middle Eastern Roman Empire. Theme (Byzantine district):  They were established in the mid-7th century in the aftermath of the Slavic invasion of the Balkans and Muslim conquests of parts of Byzantine territory, and replaced the earlier provincial system established by Diocletian and Constantine the Great.
i don't know