Constantine lived his entire life within the imperial court, which he saw as the central institution of Roman life. He believed that the emperor’s job was to defend the empire from external foes while creating a more just and ordered society for his subjects; he can often be seen acting on those principles. At the same time, his powerful personality led him to commit acts of violence against those closest to him. A deeply complex man of seemingly boundless energy, Constantine was remembered in later generations not only as the first Christian emperor, but as the emperor who shaped the future course of the Roman world.
—David Potter, Constantine The Emperor (Oxford: OUP, 2013), 2.