Khosrau I
Justin reportedly suffered from temporary fits of insanity and was unable to perform his duties as early as the fall of Dara to Khosrau I of the Sassanid Empire in November, 573. According to Gregory of Tours, Sophia assumed sole power over the Empire at this point. Evagrius Scholasticus reports that Sophia concluded a three-year truce with Khosrau on her own.