Justinian I, also known as Justinian the Great, was the Eastern Roman Emperor from 527 to 565. His reign is marked by the ambitious 'renovatio imperii' (restoration of the Empire), seeking to recover the lost Western provinces.
His generals, notably Belisarius and Narses, reconquered the Vandal Kingdom in North Africa, the Ostrogothic Kingdom in Italy, and parts of Spain. However, these wars were costly and strained the empire's resources.
Beyond military conquests, he sponsored the Codex Justinianus (Code of Justinian), which became the foundation of civil law in many modern states, and commissioned architectural masterpieces like the Hagia Sophia. His reign also saw the devastating Plague of Justinian.