Although he could not hold Italy, the red line seen in the illustration shows the extent of the area in which he had influence, not just control.
Despite operating out of Constantinople/Byzantium, and despite the tendency to think of this as the Byzantine Empire, Justinian and his people felt they were the extension and continuation of the Christian Roman Empire. (My recent posts refer to the soldiers sent by Justinian as Byzantines because of the name of the city, not some national identity).
Petrus Sabbatius Iustinianus was born in 482 in what is now southern Serbia, east of Kosovo, near where he later founded the city of Justiniana Prima in 535. He also made it the seat of a new archbishopricIt is currently an archaeological site, and was only occupied until 615 CE.
His mother was Vigilantia, a sister of an army commander named Justin, who later became emperor. Justin I adopted Justinian and took him to Constantinople to ensure a good education and future for the boy. Justinian learned theology, Roman history, and law. His native language was Latin, and he was possibly the last emperor in Constantinople who was a native speaker, since his successors were all from Greek-speaking areas.
He ruled from 527 to 565. In that time he accomplished many things that weren't all about defending or conquering territory. For instance, he instigated major overhauling of the Corpus Juris Civilis, the body of Roman civil law. He was responsible for rebuilding the Hagia Sophia, the Dome of the Holy Wisdom. He was called "the emperor who never sleeps" for his ambitious plans and work ethic.
One of the issues he had to deal with during his reign was the matter of Chalcedonian Christianity. Justinian was a Chalcedonian. What made him different and why it was controversial is a topic for next time.