Technically, Constantine became co-emperor with his brother when Basil assumed the throne in 976 at the age of 18, but during the 49 years that Basil II ruled, his brother had little role in the affairs of state even though Basil was often away from Constantinople fighting wars. Constantine is said to have spent most of this time living in luxury and with little or no responsibility.
When Basil died on December 15, 1025, Constantine finally became sole emperor, although he ruled for less than three years before his own death on November 15, 1028. Although he called off his brother's plans for future military expeditions, he appears to have ruled effectively despite his past reputation.
Like his brother, Constantine died without a male heir. The empire thus passed to his daughter Zoë and a long line of her husbands and children, none of whom distinguished themselves.