The Legion was recruited under direction of
Pope Pius IX's secretary of state, Cardinal
Giacomo Antonelli, following the
September Convention of 1864, to replace French troops garrisoned in Rome, during the closing phase of
Italian unification, the
Risorgimento. The September Convention permitted the Pope to keep an army, but it did not give
Napoleon III the right to continue to maintain forces in Rome, supporting papal temporal power in the rump
Papal States. After the
battle of Mentana, fought on 3 November 1867 between French-Papal troops and the Italian volunteers, led by
Giuseppe Garibaldi, it became public knowledge that the "Legion" was composed of
French Imperial recruits from
Antibes lying on the
Mediterranean coast close to the border with
Piedmont. Its "services to the Pope were rendered as services to the French Empire", the former Prime Minister of Italy,
Francesco Crispi recalled in 1891. "It is singular that on the dead bodies were found livrets (pay books) from French regiments, to which every one of these men belonged, with the number of his matriculation, and with formula of the oath of fidelity to the Emperor". No formal denunciation of French intervention so contrary to the spirit of the September Convention was lodged, however. A frank remark of the French minister
Jules Favre with the Italian ambassador
Costantino, Count Nigra, 6 September 1874, allowed the obvious: "The convention of September 15th is very dead". Antonelli continued to call for the Catholic powers of Europe to come to the aid of the Pope, but there was no response. ==Strength==