Complex sentence: Theodora (Greek: Θεοδώρα, c.815-after 867) was a Byzantine Empress as the spouse of the Byzantine emperor Theophilus, and Regent of the Byzantine Empire from 842 to 855.
Split into simpler sentences: Theodora (Greek: Θεοδώρα, c.815-after 867) was a Byzantine Empress as the spouse of the Byzantine emperor Theophilus. She was the Regent of the Byzantine Empire from 842 to 855.