De Ceremoniis
In Spring, 900, Leo VI married Eudokia. His previous two wives had predeceased him. "De Ceremoniis" by Constantine VII names as many as three daughters born of the previous marriages but no son. Leo wanted to secure his succession by this marriage. George Alexandrovič Ostrogorsky points that a third marriage was technically illegal under Byzantine law and against the practices of the Eastern Orthodox Church at the time. Leo VI had to seek permission by Ecumenical Patriarch Antony II of Constantinople.