Justinian I, Eastern Roman emperor.

Justinian I (482 - 565), also known as Justinian the Great or Saint Justinian the Great, was the nephew of Emperor Justin I, originally born from a peasant family in Tauresium. Justin, before he became emperor, adopted Justinian and raised him in Constantinople. Justinian served in the Imperial Guard, the Excubitors, just as his uncle had, and was made associate emperor in 527 before becoming sole emperor when Justin died in the same year. Justinian was ambitious and clever, and sought to revive the empire's greatness, planning the reconquest of the western half of the Roman Empire in what was known as renovatio imperii (restoration of the Empire). Justinian was hard-working and known as 'the emperor who never sleeps'. He nearly lost his throne during the Nika riots, and nearly lost his life during the Justinian Plague of the early 540s. Justinian was a devout Christian and theologian, and his partial recovery of lost Roman territories led him to be called by some as one of the 'last Romans'. His uniform rewriting of Roman law, the 'Corpus Juris Civilis' is perhaps his greatest legacy, which is still used as the basis of civil law in many modern nations. His restoration activities included the building of the Hagia Sophia. He died in 565 without an heir, succeeded by his nephew Justin II. (Photo by: Pictures From History/Universal Images Group via Getty Images)