Columbia subject headings:
Byzantine Empire--Relations--Holy Roman Empire.
Church and state--Byzantine Empire--History.
Church history--Primitive and early church, ca. 30-600.
Empresses--Byzantine Empire--Biography.
Empresses--Rome--Biography.
Helena, Saint, approximately 255-approximately 330.
Holy Roman Empire--Relations--Byzantine Empire.
Leadership in women--Byzantine Empire--History.
Orthodox Eastern Church--Byzantine Empire--History.
Theophano, Empress, consort of Otto II, Holy Roman Emperor, 958-991.
Harvard subject headings:
Byzantine Empire--Relations--Holy Roman Empire.
Church and state--Byzantine Empire--History.
Church history--Primitive and early church, ca. 30-600
Church history--Primitive and early church, ca. 30-600.
Empresses--Byzantine Empire--Biography
Empresses--Rome--Biography
Helena, Saint, approximately 255-approximately 330.
Holy Roman Empire--Relations--Byzantine Empire.
Leadership in women--Byzantine Empire--History.
Orthodox Eastern Church--Byzantine Empire--History.
Theophano, Empress, consort of Otto II, Holy Roman Emperor, 958-991.
Princeton subject headings:
Holy Roman Empire--Church history.
Holy Roman Empire--History--To 1517.
Holy Roman Empire--Kings and rulers.
Queens--Holy Roman Empire--History.