With Tarasicodissa therefore the Emperor Leo entered into a compact of mutual defence. The Isaurian dropped his uncouth name and assumed the classical and philosophical-sounding name of Zeno; he received the hand of Ariadne, daughter of the Emperor, in marriage, and as Leo had no male offspring, the little Leo, offspring of this marriage and therefore grandson of the aged Emperor, was, in this monarchy which from elective was ever becoming more strictly hereditary, generally accepted as his probable successor.
As it had been planned so it came to pass. Leo the Butcher died (3d Feb. 474); the younger Leo, a child of seven years old, was hailed by Senate and People as his successor: Zeno came at the head of a brilliant train of senators, soldiers, and magistrates, to "adore" the new Emperor, and the child, carefully instructed by his mother in the part which he had to play, placed on the bowed head of his father the Imperial diadem. This act of "association" as it was called, generally practised upon a son or nephew by a veteran Emperor anxious to be relieved from some of the cares of reigning, required to be ratified by the acclamations of the soldiery; but no doubt these acclamations, which could generally be purchased by a sufficiently liberal donative, were not wanting on this occasion. Zeno, otherwise called Tarasicodissa the Isaurian, was now Emperor, and nine months after, when his child-partner died, he became sole ruler of the Roman world, except in so far as his dignity might be considered to be shared by the phantom Emperors of the West, who at this time were dethroning and being dethroned with fatal rapidity at Rome and Ravenna.