Wikipedia
The Alexiad is a medieval historical and biographical text written around the year 1148 by the Byzantine historian and princess Anna Komnene, daughter of Emperor Alexios I Komnenos.
In the Alexiad, Komnene describes the political and military history of the Byzantine Empire during the reign of her father, the Byzantine emperor, which makes it a reference on the Byzantium of the High Middle Ages. The Alexiad documents the Byzantine Empire's interaction with the First Crusade (despite being written nearly fifty years afterwards), and the text highlights the conflicting perceptions of the East and West in the early 12th century.
The text was written in a form of artificial Attic Greek, and shows the Byzantine perception of the Crusades.