Such was the importance of Malta when the Knights took over the island in 1530. The first need was to put it into a state of defence. On the northeast of the island was the promontory of Mount Sceberras, flanked by the two fine harbours, the Marsa Muscetto and what was later known as the Grand Harbour.[3] The eastern side of the Grand Harbour was broken by three prominent peninsulas, later occupied by Fort Ricasoli, Fort St. Angelo, and Fort St. Michael. The only fortification in 1530 was the Fort of St. Angelo, with a few guns and very weak walls. The intention of the Knights, even from the beginning, was to make the main peninsula, Mount Sceberras, the seat of their "Convent"; but as that would mean the leveling of the whole promontory, a task of enormous expense and difficulty, and as immediate defence was necessary, they decided to occupy the Peninsula of St. Angelo for the present. Wedged between St. Angelo and the mainland there was a small town, "Il Borgo": this, for the present, the Knights made their headquarters, drawing a line of entrenchments across the neck of the promontory to guard it from the neighboring heights.
When it became certain that Malta was to be its permanent home--for L'Isle Adam had at first cherished hopes of recapturing Rhodes--the Order proceeded to take further measures for its security. Both St. Angelo and Il Borgo were strengthened with ramparts and artillery, and the fortifications of the Città Notabile, the main town in the centre of the island, were improved. In 1552 a commission of three Knights with Leo Strozzi, the Prior of Capua, at its head--one of the most daring Corsairs of the day--made a report of the fortifications of the island. They recommended strengthening Il Borgo and St. Angelo, and pointed out that the whole promontory was commanded by St. Julian, the southernmost of the three projections into the Grand Harbour. Further, as it was necessary to command the entrances both of Marsa Muscetto and of the Grand Harbour, the tip, at least, of Mount Sceberras should be occupied, as the finances of the Order would not allow of anything further being done. These recommendations were carried out, and Fort St. Michael was built on St. Julian and Fort St. Elmo on the end of Mount Sceberras. A few years later the Grand Master de la Sangle supplied the obvious deficiencies of St. Julian by enclosing it on the west and the south by a bastioned rampart.