Flavius Mar(cianus?) Petrus Theodorus Valentinus Rusticius Boraides Germanus Iustinus, simply and commonly known as Justin (, ; circa 525–566), was an East Roman (Byzantine) aristocrat and general. A member of the Justinian Dynasty and nephew of Emperor Justinian I (r. 527–565), he was appointed as one of the last Roman consuls in 540, before going on to assume senior military commands in the Balkans and in Lazica. He fought against the Slavs, the Sassanid Persians and supervised the Byzantine Empire's first contacts with the Avars. At the time of Justinian's death, he was seen as a probable successor, but was beaten to the throne by his cousin, Justin II (r. 565–578), who exiled him to Egypt, where he was murdered.