Theophano
Theophano was a Byzantine empress. She was the wife of Romanus II; wife and murderer of Nicephorus Phocas; lover of John I Tzimisces ; the mother of Basil II and Constantine VIII.
Becoming 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 needed to align her interest with the strongest general at the time, Nicephorus Phocas. As the army had already proclaimed 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 obtained legitimacy by connecting to the Macedonian dynasty.
Betrayal
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 assassination 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)
Downfall
But Theophano was badly miscalculated in the hope of becoming the wife of the new ruler. Slain Nicephorus found his avenger in the Patriarch Polieuctus, who was determined to punish the crime. He demanded John to repent, to punish the murderers (his helpers and friends), and to remove Theophano from the court. John was forced to submit to Patriarch’s requests. Only then he was allowed to enter in church and complete his crowning ceremony.
Theophano was sent to exile and did not return to the capital until her sons acceded to the throne.
Sources
History of the Byzantine State by Georgije Ostrogorski