Tiberius II Constantine (520-582) was born in Thrace and was a close friend to future emperor Justin II. Tiberius became commander of the Excubitors imperial guard, and when Justin II became emperor, Tiberius was made his chief military commander. When Justin had a mental breakdown, his wife Sophia turned to Tiberius to manage the empire, and he was later named co-emperor and adopted son by Justin in 574. Tiberius became sole emperor after Justin died in 578.