Answer: Building projects completed by Emperor Justinian
Explanation:
Emperor Justinian is widely considered the greatest Roman/Byzantine emperor after the fall of the Western Roman Empire for his various achievements including reconquering much of the area that the Western Roman Empire lost when it was dissolved as well as his sponsorship of the Justinian Code which became the basis of the Legal System of the Byzantine empire for close to a millennia.
He also initiated building projects to help the people of the empire such as schools, churches, public baths and aqueducts. Justinian was also responsible for building the Hagia Sophia which was one of the largest churches ever built.