Piero Della Francesca painted the following Fresco to depict battle between Heraclius of Byzantine Empire and Khosrou II of Persian Empire.
Which regions or dynasties do the flags represent?
From what I can guess:
Black Eagle on Golden field represents the Emperor of Eastern Roman Empire, Heraclius. (As the single headed Roman Eagle remained in use in ERE, albeit rarely. This is attested by presence of Eagle Bearers (Aquilifers/ὀρνιθόβορας) in ERE).
Golden lion on Red field probably represents Macedonia. Pictured below, Coat of Arms of Macedonia from 16th century which represents the ancient Lion of Macedonia:
It might also be a flag from Armenia as Armenians also used a lion emblem occasionally. Pictured below, a flag of King of Armenia (German Caption on top reads "Der Konig von der Hindern Armenia" and the image also appears in this 16th century book):
The Black head with white Bandanna represents Corsica (even though the flag was adopted centuries after the battle or the painting
and I am not sure if Corsica was part of ERE back thenbut it was a part of ERE back then). Pictured below, flag of Corsica:
The White Cross on Red field seems to be flag of Duchy of Savoy but that can't be right as Savoy was never a part of ERE. Pictured below flag of Savoy:
The white duck on
redgreen field is harder to guess. Maybe it is a swan? If yes, it could be flag of Malta as Pieta, Malta's coat of arms are a white swan on a black field.
So which regions do these flags represent? Or did the artist just made them up in his head?
P.S. Pardon me if I am mistaking between red and green color here.