Chapter VIII, of Cassells Illustrated History of England, Volume 9 page 6

By keeping a French corps in the Roman territory, the Emperor of the French knew that he gave continual umbrage to the Liberal sentiment of Europe; he was therefore anxious to withdraw his troops, yet so that Rome should be left secure from attack, whether from the Italian Government or the partisans of the Revolution. Thus arose the famous Convention between France and Italy of the 15th September, 1864, the principal articles of which were these: - 1. Italy engaged not to attack the territory then belonging to the Pope, and to prevent, even by force, every attack on that territory from without. 2. France undertook to withdraw her troops from the Pontifical States in proportion as the Pope's army should be organised; but the evacuation was, under any circumstances, to be completed within the space of two years. 3. The Italian Government engaged to raise no protest against the organisation of a Papal army, even if composed of foreign volunteers, sufficient to maintain the Pope's authority and tranquillity as well in the interior as upon the frontier of his states, provided always that this force should not degenerate into a means of attack against the Italian Government. 4. Florence was to be substituted for Turin as the capital. This last stipulation was insisted on by the French Emperor, because it was evident to all that the capital of the Italian kingdom could not much longer remain at Turin - a city exposed on two sides to a sudden invasion across the Alps; if, then, it were once removed to the other side of the Apennines and fixed at Florence, not at Rome, he calculated that there it would probably remain, and that the ardent longing for Rome, as the natural and necessary capital of Italy, would gradually fade away from the Italian heart. Thus only, he considered, was it possible to reconcile the urgent claim of French Catholics, that the Pope should be protected, with the political and military necessity which compelled the Italians to seek a more central position for their capital. But in the Italian intellect the Emperor encountered an adversary not less tenacious, not less wily, than himself, and endowed besides with a swift, flashing audacity which was foreign to his own character. The Italians thought it a clear gain that the French eagles should be withdrawn from their soil, and trusted to the chapter of accidents to bring them to Rome at last. Cialdini, in an eloquent speech to the Senate, counselling the removal of the capital to Florence, made no secret of his ulterior aims. He fully concurred, he said, in the opinion ascribed to the great Napoleon, that Florence was not sufficiently central to be the capital of Italy, " and exactly for that reason I desire and hope to go to Rome." The discontent of the people of Turin, at the prospect of losing the advantages which had hitherto accrued to their city from being the seat of Government, broke out into open rioting; the troops had to be called out, and several lives were lost before the tumult was quelled.