Theophanu (; also Theophania, Theophana, or Theophano; Medieval Greek ; AD 955 15 June 991) was empress of the Holy Roman Empire by marriage to Emperor Otto II, and regent of the Empire during the minority of their son, Emperor Otto III, from 983 until her death in 991. She was the niece of the Byzantine Emperor John I Tzimiskes. She was known to be a forceful and capable ruler. Her status in the history of the Empire in many ways was exceptional. According to Wilson, "She became the only consort to receive the title 'co-empress' (coimperatrix augusta), and it was envisaged she would succeed as sole ruler if Otto II died without a son." Early life According to the marriage certificate issued on 14 April 972 Theophanu is identified as the neptis (niece or granddaughter) of Emperor John I Tzimiskes (925–976, reigned 969–976) who was of Armenian and Byzantine Greek descent. She was of distinguished noble heritage: the Vita Mahthildis identifies her as augusti de palatio and the Annales Magdeburgenses describe her as Grecam illustrem imperatoriae stirpi proximam, ingenio facundam. Recent research tends to concur that she was most probably the daughter of Tzimiskes' brother-in-law (from his first marriage) Constantine Skleros (c. 920–989) and cousin Sophia Phokas, the daughter of Kouropalatēs Leo Phokas, brother of Emperor Nikephoros II (c. 912–969). Marriage Theophanu was not born in the purple as the Ottonians would have preferred. The Saxon chronicler Bishop Thietmar of Merseburg writes that the Ottonian preference was for Anna Porphyrogenita, a daughter of late Emperor Romanos II. Theophanu's uncle John I Tzimiskes had overthrown his predecessor Nikephoros II Phokas in 969. Theophanu was escorted back to Rome for her wedding by a delegation of German and Italian churchmen and nobles. When the Ottonian court discovered Theophanu was not a scion of the Macedonian dynasty, as had been assumed, Otto I was told by some to send Theophanu away. His advisors believed that Theophanu's relation to the usurper John Tzimiskes would invalidate the marriage as a confirmation of Otto I as Holy Roman Emperor. He was persuaded to allow her to stay when it was pointed out that John Tzimiskes had wed Theodora, a member of the Macedonian dynasty and sister to Emperor Romanos II. John was therefore a Macedonian, by marriage if not by birth. Otto I must have been convinced, because Theophanu and Otto's heir, Otto II, were