Res Gestae

Then, after Zeno was made emperor by his son Leo,[*](Leo the Thracian, also called Leo the Great, having no son, named his son-in-law Zeno as his successor. Since the people of Constantinople did not approve the choice, Leo associated with himself his grandson Leo, who survived him a few months only.) who was the offspring of the daughter of Leo the Great, Ariagne by name, he reigned for a year with his son Leo, and it was through Leo’s merit that Zeno retained his power. But after sharing the rule with his son for one year, Zeno was emperor for fourteen years more; he was an Isaurian of high rank, trained to arms, and worthy to receive an emperor’s daughter in marriage.