1. constructed the city of Constantinople = Constantine I
Prior to being renamed as Constantinople, this city was called Byzantium. However, when Constantine I came to the throne, he decided to name the city after himself - thus, Constantinople was born in 330 AD. Constantinople is today's Istanbul, the most populous city in Turkey.
2. created a code from which the Byzantine Empire derives its laws = Justinian I
Emperor Justinian I wanted to reform his empire, which is why he came up with a set of laws known as the Justinian Code in the 6th century. He wanted to revise the old Roman law and incorporate new ideas and rules into a new set of rules.
3. resolved the conflict between the empire and the church by restoring the use of icons = Empress Theodora
Theodora was the wife of Emperor Theophilos, a staunch iconoclast, meaning he supported the banning of icons. On the other hand, his wife fought for reinstatement of icons into churches, after which she was venerated as a saint.
