Byzantine Emperor Justin I names his nephew Justinian I as co-ruler and successor.
Justinian I wil rule as Byzantine Emperor (527-565) and become known as Justinian the Great. The last emperor to speak Latin as his first language, Justinian I will attempt to restore the original Roman Empire — he won't succeed, but he will greatly expand the borders of the Byzantine Empire and influence the empire for a long time to come.
It is thought that Justinian I was already acting as a virtual emperor long before being officially named to the position by Justin I. In fact, Justin only achieved the throne in 518 with significant help from Justinian. As Justin grows older he is reported to become rather senile, making Justinian I the sole ruler even before Justin's death later this year.