Theophano (Byzantine Empress)
This unusually beautiful but utterly amoral woman played an important role in the Byzantine history. She was an innkeeper's daughter and her real name was Anastasia. Around 956 , the emperor Romanus II fell in love with her and married her, subsequently renaming her Theophano.
Partnership with Nicephorus Phocas
On March 15, 963, Emperor Romanus II unexpectedly died at the age of twenty-six. His sons Basil II and Constantine VIII were heirs and Theophano was named regent. However she realized that to secure power she needs to align her interest with the strongest general at the time, Nicephorus Phocas. As the army already proclaim him as a Emperor in Cesarea, Nicephorus entered Constantinople on August 15, broke the resistance of Joseph Bringas ( a eunuch palace official who had become Romanus' chief council) in bloody street fights, and on 16 August he was crowned in Hagia Sophia. After that he married Theophano. This way he got the legitimacy by connecting to the Macedonian dynasty.
However, not too long after, she became lover to a young and brilliant general, John Tzimisces. They soon began to conspire against Nicephorus . She prepared the assasination and John and his friends implemented it on the night between 10 and 11 December 969. The emperor was now John I Tzimisces (969-976)
But Theophano was badly miscalculated in the hope of becaming wife of the new ruler. Slain Nicephorus found his revenger in the Patriarch Polyeuctus, who was determined to punish the crime. He demanded of John to repent, to punish the murderers (his helpers and friends), and to remove Theophano from the court. John was forced to submit to the Patriarch’s requests. Only then was he allowed to enter in church and complete his crowning ceremony.
Theophano was sent into exile and was not back in the capital before her sons acceded to the throne.
History of the Byzantine State by Georgije Ostrogorski