John the Deacon (c.940–c.1018; also Giovanni da Venezia, Giovanni Diacono, Iohannes Diaconus or Iohannes Venetus) was a Venetian chronicler and secretary to doge Pietro Orseolo II.
The “Istoria Veneticorum” from around the year 1000, is the first work in the historiography of Venice.
The “Chronicon Altinate” is one of the central medieval sources to early Venetian history, used extensively since it was written.