Pannonian cap

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In the period of the Tetrarchy, the Pannonian cap (pileus pannonicus) was adopted as the main military cap of the Roman army, until the 6th century AD; it was worn by lightly armed or off-duty soldiers, as well as workmen.[2][3][10] It often appears in Roman artwork, in particular mosaics, from the late 3rd century AD. The earliest preserved specimen of the hat was found at the Roman quarry of Mons Claudianus, in the eastern desert of Egypt, and is dated to 100–120 AD; it has a dark-green color, and looks like a low fez or pillbox hat.[10][30]