In the sixth century a.d., Procopius of Kaisareia (Palestine) wrote eight books on the wars against the Persians, Vandals and Goths, as well as a book on the building activity in the reign of Justinian I. Whereas his history of war is the work of an objective historian, his so-called "secret history" (historia arcana) is filled with gossip and rumors that circulated within the imperial court. Procopius is a source to both historians and philologists.