Sequin of Doge <a href="//commons.wikimedia.org/wiki/Pietro_Gradenigo" class="mw-redirect" title="Pietro Gradenigo">Pietro Gradenigo</a> of Venice (1289–1310).
No explicit credit
H.F. Helmolt, <i>History of the World</i>, Volume VII, Dodd Mead 1902. Plate between pages 68 and 69.