On the 22d of November a summons was sent to the French to evacuate the Papal States and Malta, and a Neapolitan army marched upon Rome, commanded by Mack in person.  At the same time Nelson took on board his squadron a corps of five thousand, to seize Leghorn, the possession of which, with control of the sea, was not unjustly considered threatening to the communications between the centre of French power, in Northern Italy, and the exposed corps at the foot of the peninsula.  After landing this body, Nelson again went to Naples, leaving Troubridge in charge at Leghorn, with several ships; directing him also to keep vessels cruising along the Riviera, and before Genoa, to break up the coastwise traffic, which had resumed great proportions since the absence of the British from the Mediterranean, and upon which the French army in Piedmont and Lombardy now greatly depended.

On the 5th of December the “Vanguard” once more anchored at Naples.  Nelson’s estimate of affairs as he now found them, is best told in his own words.  “The state of this Country is briefly this:  The army is at Rome, Civita Vecchia taken, but in the Castle of St. Angelo are five hundred French troops.  The French have thirteen thousand troops at a strong post in the Roman State, called Castellana.  General Mack is gone against them with twenty thousand:  the event in my opinion is doubtful, and on it hangs the immediate fate of Naples.  If Mack is defeated, this country, in fourteen days, is lost; for the Emperor has not yet moved his army, and if the Emperor will not march, this country has not the power of resisting the French.  But it was not a case of choice, but necessity, which forced the King of Naples to march out of his country, and not to wait till the French had collected a force sufficient to drive him, in a week, out of his kingdom.”  It is by no means so sure that no other course of action had been open, though Nelson naturally clung to his first opinion.  By advancing, the King gave the French occasion, if they were seeking one; and the Neapolitan army, which might well have deterred them, as it had embarrassed even Bonaparte in his time, had its rottenness revealed as only trial can reveal.  When reviewed, it had appeared to Mack and Nelson a well-equipped force of thirty thousand of the “finest troops in Europe.”  Brought face to face with fifteen thousand French, in a month it ceased to exist.

Upon Mack’s advance, the French general Championnet had evacuated Rome, into which the King made a vainglorious triumphal entry.  The French retired to Castellana, followed by the Neapolitans; but in the campaign that ensued the latter behaved with disgraceful cowardice.  Flying in every direction, with scarcely any loss in killed, and preceded in their flight by the King, the whole force retreated in confusion upon the capital.  There revolutionary ideas had spread widely among the upper classes; and, although the populace both in city and country remained fanatically loyal, and hostile to the French, the King and Queen feared to trust their persons to the issue of events.  Powerless through suspicions of those around them, apparently well founded, and through lack of any instrument with which to act, now that their army was destroyed, their one wish was to escape to Palermo.