Answer the following question: Information:  - A historian is a person who researches, studies, and writes about the past, and is regarded as an authority on it. Historians are concerned with the continuous, methodical narrative and research of past events as relating to the human race; as well as the study of all history in time. If the individual is concerned with events preceding written history, the individual is a historian of prehistory. Although "historian" can be used to describe amateur and professional historians alike, it is reserved more recently for those who have acquired graduate degrees in the discipline. Some historians, though, are recognized by publications or training and experience. "Historian" became a professional occupation in the late nineteenth century as research universities were emerging in Germany and elsewhere.  - Anna Komnene ("Ánna Komnn"; 1 December 1083  1153), commonly Latinized as Anna Comnena, was a Byzantine princess, scholar, physician, hospital administrator, and historian. She was the daughter of the Byzantine Emperor Alexios I and his wife Irene Doukaina. She wrote the "Alexiad", an account of her fathers reign, which is unique in that it was written by a princess about her father.  - The Battle of Manzikert was fought between the Byzantine Empire and the Seljuq Turks on August 26, 1071 near Manzikert (modern Malazgirt in Mu Province, Turkey). The decisive defeat of the Byzantine army and the capture of the Emperor Romanos IV Diogenes played an important role in undermining Byzantine authority in Anatolia and Armenia, and allowed for the gradual Turkification of Anatolia.  - John II Komnenos or Comnenus ("Ianns II Komnnos"; September 13, 1087  8 April 1143) was Byzantine Emperor from 1118 to 1143. Also known as "John the Beautiful" or "John the Good" ("Kaloïanns"), he was the eldest son of Emperor Alexios I Komnenos and Irene Doukaina and the second emperor to rule during the Komnenian restoration of the Byzantine Empire. John was a pious and dedicated monarch who was determined to undo the damage his empire had suffered following the battle of Manzikert, half a century earlier.  - Irene Doukaina or Ducaena ( Greek :   , Eirn Doukaina ) ( c. 1066 -- 19 February 1138 ) was the wife of the Byzantine emperor Alexios I Komnenos , and the mother of the emperor John II Komnenos and of the historian Anna Komnene .  - A physician, medical practitioner, medical doctor or simply doctor is a professional who practises medicine, which is concerned with promoting, maintaining, or restoring health through the study, diagnosis, and treatment of disease, injury, and other physical and mental impairments. Physicians may focus their practice on certain disease categories, types of patients and methods of treatmentknown as specialitiesor they may assume responsibility for the provision of continuing and comprehensive medical care to individuals, families, and communitiesknown as general practice. Medical practice properly requires both a detailed knowledge of the academic disciplines (such as anatomy and physiology) underlying diseases and their treatmentthe "science" of medicineand also a decent competence in its applied practicethe art or "craft" of medicine.    Given the information above, choose from the list below the object entity that exhibits the relation 'country of citizenship' with the subject 'irene doukaina'.  Choices: - academic  - byzantine empire  - germany  - turkey
Answer:
byzantine empire