A few days after, he again left Rome, with the Roman army, and was in the vanguard, having under his orders the First Italian Legion, of eleven hundred men; the Third of the line, eight hundred; fifty cavalry, and two light guns.
At Valmontone he received advices that the Neapolitans were sending back their baggage and heavy artillery, and he therefore concluded that they were retreating, and pressed forward, sending notice to the principal corps. At Monte Fortino he received more positive information, and continued to advance with haste. About eight o'clock A. M. he was in sight of Velletri, which was on the road, and two miles distant. He then discovered the enemy's cavalry, in échellon, on the Appian Way, to protect the retreat of their army, for which they were preparing. The main body of the Neapolitan army was then at Velletri; and, as soon as Garibaldi's corps was discovered by them, the Neapolitans moved to attack it.
He drew up the Third of the line, in échellon, by companies, near the road, which was among hills covered with vineyards, to protect his retreat in case of necessity, and to act as a reserve in case the enemy should attack. He placed the First Italian Legion on both sides of the road, in the best position he could, and thus awaited the assault of the enemy, leaving two companies in column in the road itself. The cavalry and artillery he placed in positions adapted to be most serviceable.
The enemy attacked: but all their attempts were fruitless. They had many killed, and were finally obliged to shut themselves up in the city, on the defensive.
Garibaldi's corps alone was too weak to prevent the retreat of the enemy, which was finally effected by night.
The principal corps of the Roman army, of seven thousand men, under Roselli, arrived late, and tired with their march. An attempt, however, was made to attack the city in front, by charging, at the head of the First Roman Legion, with the battalion of artillery placed in a good position upon the road. The Neapolitans sustained the positions of the city, in which they remained the rest of the day. The Republicans took positions, in order to renew the attack the next day: but in the morning the Neapolitans retreated, and disappeared from Velletri.
These bold and successful operations, so briefly described, were of the highest importance, in their results, both by driving back the enemy, by encouraging the Republicans, and by adding to their reputation. The rout of the Neapolitans was so decisive, that they gave no further annoyance, and never appeared again during the war.
As for the poor Spanish army, which had landed on the coast, in obedience to the call of the poor Pope, they did nothing but issue a few bombastic proclamations, and kept themselves out of harm's way.
The French, in the meantime, were preparing to take decisive measures against Rome. The wounded, whom they had left behind them on the 30th of April, had been tenderly nursed by the Roman ladies, who had volunteered to attend at the hospitals; and three or four hundred prisoners had been harangued in the Corso, by the commander-in-chief, addressed as brother-republicans, in the name of the government and people, and dismissed without exchange or parole, with open gates, to return to Civitavecchia. On their arrival there, however, full of their praises of the noble Romans, they were immediately shipped for France, for fear of their influence among the troops.
The French army soon moved, in great force, for Rome, with heavy artillery and all preparations for a siege. But their first step was to violate the amnesty, by suddenly attacking the outposts, the night before the time limited by the armistice, and while they were almost unprotected.