Justinian I (1 August 527 - 14 November 565). Flavius Petrus Sabbatius Iustinianus Augustus, commonly known as Justinian the Great, reconquered the Mediterranean for the Byzantine Empire. He built the Great Church of St. Sophia and codified Roman law. The Golden Age of Justinian came to an end when he died on the night of November 13/14, 565. He left no children, and was succeeded by his nephew, Justin II.