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.
i don't know