To complete the deception of the enemy the Garibaldian artillery, under Colonel Orsini, was ordered to make a retrograde march on Corleone previous to joining the main force at Misilmeri. Orsini narrowly escaped getting caught while executing this movement, and for the sake of celerity was obliged to throw his five cannon (including one taken at Calatafimi) down deep water courses. He returned to pull them out again when the immediate danger was past. General Colonna, who followed him closely, was convinced that the whole of the Garibaldians were in disorderly retreat as witnessed by the mules and waggons purposely abandoned by Orsini along the route. For four days Colonna believed that he had Garibaldi flying before him, and sent intelligence to that effect to Naples, whence it was published through the world. On the fifth day he was immeasurably surprised by hearing that Garibaldi had entered Palermo!
It was at early dawn on Whitsunday, the 27th of May, that Garibaldi reached the threshold of the capital, and after overcoming the guard at Ponte dell' Ammiraglio, pushed on to Porta Termini, the strategic key to the city. The royalists, though taken by surprise in the first instance, had time to dispose a strong force behind walls and barricades before Garibaldi could reach the gate, and it required two hours of severe fighting to take the position. Many Red-shirts were killed, and Benedetto Cairoli received the severe wound from which he never wholly recovered. Success, however, was complete, and the Palermitans got up to find, to their frantic joy, the Liberator within their gates. According to the old usage their first impulse was to run to the belfries in order to sound the tocsin, but they found that the royalists had removed the clappers of the bells. Nothing daunted, they beat the bells all day with hammers and other implements, and so produced an indescribable noise which had a material influence on the nerves of the terrified Neapolitan troops. Being disarmed, the only other help which the inhabitants could render to their deliverers was the erection of barricades.
Even after Garibaldi's entry, it is thought that General Lanza could have crushed him in the streets by sheer force of superiority in numbers and artillery had he made proper use of his means. However, at about three p.m., he chose the less heroic plan of ordering the castle and the Neapolitan fleet to bombard the city. Most of his staff opposed the decision, and one officer broke his sword, but Lanza was inexorable. The measure so exasperated the Palermitans that even had it achieved its end for the moment, never after would they have proved governable from Naples. Thirteen hundred shells were thrown into the city. Lord Palmerston denounced the bombardment and its attendant horrors as 'unworthy of our time and of our civilisation.' The soldiers helped the work by setting fire to some quarters of the city. Among the spots where the shells fell in most abundance was the convent of the Sette Angeli. The Garibaldians escorted the nuns to a place of safety and carried their more valuable possessions after them. The good sisters were charmed by the courtesy with which the young Italians performed these duties.