In Italian public discourse, with the notable exception of the Venetians, the Turks were portrayed as the nemesis of all Christendom. The perception that Italy, in particular, would be laid waste in the vilest way by Ottoman forces, if they could get a foothold, was heightened by the discord between Christian princes. In the Council Indiction of 1542, Paul III spoke of this vulnerability: ‘Our impious and ruthless enemy the Turk was never at rest and looked upon our mutual enmities and dissensions as his fitting opportunity for carrying out his designs with success’. In speaking of the attacks on Apulia Paul conveyed the fear and consequent action that were prevalent throughout his pontificate: ‘Meanwhile the Turk, our cruel and perpetual enemy, attacked Italy with a vast fleet, took, sacked, ravaged several cities of Apulia and carried off numbers into captivity whilst we, in the midst of the greatest alarm and the general danger, were engaged in fortifying our shores and in furnishing assistance to the neighbouring states’.

Ottoman designs had long prompted alarm among Italians, but that alarm reached new peaks in the 1530s. In August 1534, shortly before Paul's election, Barbarossa had harassed towns on the southern coast of Italy and then created a panic in Rome when his fleet suddenly appeared in the Tiber and weighed anchor near Ostia. All Barbarossa did at this time was replenish the fleet's water supplies and sail off. But he had sent a chilling message about what was possible.