The site had been previously occupied by Eustachio del Monte, a nephew of the La Valette. The Knights of Malta bought the house commissioned Gerolamo Cassar to design the palace.

The palace is built around two courtyards, one of which is predominated by a statue of Neptune. There are two entrances in the front and one entrance from Piazza Regina just west of the Bibliotecha. The entrance to the state rooms is in the Neptune Courtyard via a spiral staircase. The ceiling of this entrance was painted by Nicolo Nasini da Siena in 1724.

The Armoury, housing one of the finest collections of weapons of the period of the Knights of Malta in all of Europe, runs the width of the back of the palace. Spears, swords, shields, heavy armour and other weapons, including Dragut's sword are on display.

St. Johns Co-Cathedral, located in Valletta, Malta, was built by the Knights of Malta between 1573 and 1578 having been commissioned in 1572 by Grand Master Jean de la Cassière as the conventual church of the Order of the Knights Hospitaller of St John, known as the Knights of Malta. The Church was designed by the Maltese military architect Gerolamo Cassar who has designed several of the more prominent buildings in Valletta.

The inside is in sharp contrast to the facade as the extremely ornate interior [1] decorated in the height of the Baroque period. The inside was largely decorated by Mattia Preti, the Calabrian artist and Knight. Preti designed the intricate carved stone walls and painted the vaulted ceiling and side altars with scenes from the life of St John. Noteworthy is the fact that the carving was all undertaken in-place (in-stu) rather than being carved independently and then attached to the walls (stucco). The Maltese limestone from which the Cathedral is built lends itself particularly well to such intricate carving.

Near the main entrance one finds the monument of Grandmaster Fra Marc'Antonio Zondadari from Siena. He was the nephew of Pope Alexander VII.

The Valletta Royal Opera House was an opera house and performing arts venue in Valletta, Malta. It was designed by English architect Edward Middleton Barry and was erected in 1866. In 1873 its interior was extensively damaged by fire but was eventually restored by 1877. The theatre, Valletta's most imposing landmark, was bombed to the ground during World War II in 1942. It was used as one of the first performance stages for new artists.

The design of the building was entrusted to Edward Middleton Barry, the architect of Covent Garden Theatre. The original plans had to be altered due to the fact that the sloping streets on the sides of the theater hadn’t been taken into consideration. This resulted in a terrace being added on the side of Strada Reale (Republic Street).

The building of the 206 feet by 112 feet site started in 1862, after what was the Casa della Giornata was demolished. After four years, the Opera House, with a seating capacity of 1095 and 200 standing, was ready for the official opening on October 9, 1866.

The theatre was not to last long; on May 25, 1873, a mere six years after its opening, it was brought to a premature end by a fire. The exterior of the theatre was undamaged but the interior stonework was calcified by the intense heat.

It was decided to rebuild the theatre, and after the issuing of tenders for the work and a lot of arguing whether the front had to be changed or not, the theatre was ready. On October 11, 1877, after nearly four and a half years from the fire, the theatre reopened with a performance of Verdi's Aida.