THEODORA (d. 1057), daughter of the emperor Constantine VIII. Possessed of a strong and austere character, she refused the hand of the heir-presumptive, Romanus, who was married instead to her sister Zoe (1028). Though living in retirement she excited Zoe's jealousy, and on a pretext of conspiracy was confined in a monastery. In 1042 the popular movement which caused the dethronement of Michael V. also led to Theodora's instalment as joint-empress with her sister. After two months of active participation in government she allowed herself to be virtually superseded by Zoe's new husband, Constantine IX. Upon his death in 1054, in spite of her seventy years, she reasserted her dormant rights with vigour, and frustrated an attempt to supersede her on behalf of the general Nicephorus Bryennius. By her firm administration she controlled the unruly nobles and checked numerous abuses; but she marred her reputation by excessive severity towards private enemies and the undue employment of menials for advisers. She died suddenly in 5057.
See G. Finlay, History of Greece, vol. ii. (Oxford, 1877); G. Schlumberger, L'Epopee Byzantine, vol. iii.(Paris. 1905).