Born in 1889 as heir to the noble Neapolitan family of di Vituso, Guariglia graduated in law in 1908 at the University of Naples and had the connections necessary to make a career in the Italian Foreign Service, which he joined in 1909.

De Portes had separated from her noble husband and developed a tie as the long-term romantic partner of a rising French politician, Paul Reynaud.

As an Italian patriot who had loyally served the Fascist regime without developing close personal ties to Mussolini, the career diplomat was Badoglio's choice to be the Foreign Minister of what Rome hoped would be a successful neutralist government.

The result of these counter-pressures was such that six days after the hapless foreign minister and his Cabinet colleagues oversaw the signing of an armistice with the Allies on 3 September, the German army physically occupied the peninsula and carried on the war.

The foreign minister, who had earlier served as ambassador to Spain, found himself taking refuge in the Spanish Embassy in Rome, under the protection of the Francisco Franco government.