Ancona besieged in 1173 by the army of Frederick Barbarossa; led by Christian of Mainz and ally for the occasion with the Venetian Republic; which gripped the city with his ships from the harbor side. The population heroically resists the long siege of the imperial army. Print painting by Francesco Podesti 'The Oath of Ancona'; in which he discusses the episode in which a senator centennial spurs not to give the anconetanis now exhausted by famine; and they swear to resist to the death. Italy; the end of the nineteenth century.