Anna Komnene, commonly Latinized as Anna Comnena, was a Byzantine Greek princess and historian. She is the author of the Alexiad, an account of the reign of her father, Byzantine emperor Alexios I Komnenos. Her work constitutes the most important primary source of Byzantine history of the late 11th and early 12th centuries, as well as of the early Crusades. Although she is best known as the author of the Alexiad, Anna played an important part in the politics of the time and attempted to depose her brother, John II Komnenos, as emperor in favour of her husband, Nikephoros.

John II Komnenos or Comnenus was Byzantine emperor from 1118 to 1143. Also known as "John the Beautiful" or "John the Good", 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. As he was born to a reigning emperor, he had the status of a porphyrogennetos. 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.