Seven-year-old Leo II succeeds his maternal grandfather Leo I as Byzantine emperor. He dies ten months later.

Leo II, called the Younger, briefly reigned as a child emperor of the Eastern Roman Empire from 473 to 474. He was the son of Zeno, the Isaurian general and future emperor, and Ariadne, a daughter of the emperor Leo I. Leo II was made co-emperor with his grandfather Leo I on 17 November 473, and became sole emperor on 18 January 474 after Leo I died of dysentery. His father Zeno was made co-emperor by the Byzantine Senate on 29 January, and they co-ruled for a short time before Leo II died in late 474. He is sometimes surnamed with the epithet "the Small", probably to distinguish him from his grandfather and augustus Leo I.

Leo I, also known as "the Thracian", was Eastern Roman emperor from 457 to 474. He was a native of Dacia Aureliana near historic Thrace. He is sometimes surnamed with the epithet "the Great", probably to distinguish him from his young grandson and co-augustus Leo II.

The foundation of Constantinople in 330 AD marks the conventional start of the Eastern Roman Empire, which fell to the Ottoman Empire in 1453 AD. Only the emperors who were recognized as legitimate rulers and exercised sovereign authority are included, to the exclusion of junior co-emperors who never attained the status of sole or senior ruler, as well as of the various usurpers or rebels who claimed the imperial title.

January 18 is the 18th day of the year in the Gregorian calendar; 347 days remain until the end of the year.