The end of St. Elmo came with the arrival of Turkish reinforcements from Africa. New cannon batteries were placed to enfilade the fort, but even with these changes it was not until June 21st after a heavy bombardment, the Turks launched a mass assault and much to the amazement of the on lookers from Fort St. Angelo, St. Elmo was not overrun.
There above the ruins waved the flag of the Order, the Cross of St. John. But by June 23rd, there were only 100 defenders left. The Turks orders another huge bombardment. At a signal, it ceased and Mustapha order his finest troops forward, only to be thrown back, they regrouped and rushed forward through the breached walls and the fort was taken.
It had taken a month for the Turks to subdue Fort St. Elmo, much to the chagrin of Mustapha’s military advisors, who said would only take days. The cost, 8000 Turks died in the assault. The Christian forces lost 1,500. including 130 of the Knights Hospitaller.