When was the sister of Theodora Porphyrogenita died who was reigned as Byzantine Empress alongside her sister?
Theodora Porphyrogenita (11th century) Theodora Porphyrogenita (Greek: Θεοδώρα, "Theodōra" ; AD 980 – 31 August 1056) was a Byzantine Empress born into the Macedonian dynasty that had ruled the Byzantine Empire for almost two hundred years. She was co-empress with her sister Zoë for two months in 1042 and sole empress regnant from 11 January 1055 to 31 August 1056. She was the last of the Macedonian line, and upon her death the empire entered a period of decline that lasted until the ascension of Alexios I Komnenos in 1081.
Michael III Michael III (Greek: Μιχαήλ Γʹ , "Mikhaēl III"; January 19, 840 – September 23/24, 867) was Byzantine Emperor from 842 to 867. Michael III was the third and traditionally last member of the Amorian (or Phrygian) dynasty. He was given the disparaging epithet "the Drunkard" (ὁ Μέθυσος ) by the hostile historians of the succeeding Macedonian dynasty, but modern historical research has rehabilitated his reputation to some extent, demonstrating the vital role his reign played in the resurgence of Byzantine power in the 9th century.