5302811 Turkey / Byzantium: Leo IV (750-780) and Constantine VI (771-804), Byzantine emperors, from the book "Romanorvm imperatorvm effigies: elogijs ex diuersis scriptoribus per Thomam Treteru S. Mariae Transtyberim canonicum collectis", 1583; (add.info.: Leo IV (750-780), also known as Leo the Khazar, was the son of Emperor Constantine V by his first wife, Irene of Khazaria. He became co-emperor in 751, and married a noble Athenian woman also named Irene in 769. Leo became sole emperor in 775 with the death of his father. Constantine VI (771-804) was the only child of Emperor Leo IV and Empress Irene. He was crowned co-emperor in 776, and became sole emperor in 780, aged only nine. Due to his young age, his mother Irene and her chief minister Staurakios ruled in his stead. However, even when Constantine was of age at sixteen, his mother still refused to hand over executive authority to him.); Pictures from History.