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. Theodora Porphyrogenita (11th century):  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. Zoë Porphyrogenita: Zoë ( "life" ] ; 978 – June 1050) reigned as Byzantine Empress alongside her sister Theodora from April 19 to June 11, 1042.
June 1050