Constantine VIII Porphyrogenitus was de jure Byzantine Emperor from 962 until his death. He was the younger son of Emperor Romanos II and Empress Theophano. He was nominal co-emperor for 63 years (longer than any other), successively with his father; stepfather, Nikephoros II Phokas; uncle, John I Tzimiskes; and brother, Basil II. Basil’s death on 15 December 1025 left Constantine as sole emperor. Constantine displayed a lifelong lack of interest in politics, statecraft and the military, and during his brief sole reign the government of the Byzantine Empire suffered from mismanagement and neglect. He had no sons and was instead succeeded by Romanos Argyros, husband of his daughter Zoë.

The start of the decline of the Byzantine Empire has been linked to Constantine's accession to the throne. His reign has been described as "an unmitigated disaster", "a break up of the system" and the cause of "a collapse of the military power of the Empire".