Question: Helena Dragaš was the empress consort of the last reigning emperor of what empire?
Sentence (from "Constantine XI Palaiologos"): Constantine XI Dragases Palaiologos, Latinized as Palaeologus (Greek: Κωνσταντῖνος ΙΑ' Δραγάσης Παλαιολόγος , "Kōnstantinos XI Dragasēs Palaiologos", Serbian: Константин XI Драгаш Палеолог, "Konstantin XI Dragaš Paleolog" ; 8 February 1405 – 29 May 1453) was the last reigning Byzantine Emperor, reigning as a member of the Palaiologos dynasty from 1449 to his death in battle at the fall of Constantinople.
Relevant evidence: Yes