The Fresco of Guidoriccio da Fogliano
Detail from Simone Martini's fresco of
Guidoriccio da Fogliano at the Siege of Monte Massi in 1328 at
(I don't know exactly when the picture was painted, but Martini's dates
are 1284-1344, so it must have been pretty soon after the 1328 siege.)
Thanks to Bob Charrette, who found this picture.