Final answer:
The form and decor of Justinian's Hagia Sophia and San Vitale in Ravenna reinforced the idea of Christian imperium and the emperor's role as a guarantor of Christian concord.
Step-by-step explanation:
The form and decor of Justinian's Hagia Sophia and San Vitale in Ravenna reinforced the idea of Christian imperium and the emperor's role as a guarantor of Christian concord in several ways.
First, these churches were grand and awe-inspiring structures, decorated with lavish materials such as precious stones and gold. The use of such opulent materials conveyed the power and wealth of the empire, symbolizing the emperor's control over vast resources and his ability to support the growth and maintenance of these architectural marvels.
Second, the mosaics found within these churches depicted emperors and empresses, including Justinian himself, participating in religious rituals. These images emphasized the close connection between the Church and the state, suggesting that the emperor had a divine mandate to protect and promote Christianity. By showcasing emperors in a religious context, the form and decor of these churches reinforced the idea that the emperor played a crucial role in maintaining Christian concord and upholding the values of the empire.