St. John’s Co-Cathedral, Valletta: Caravaggio’s only signed painting, and 400 knights buried under the floor

On St John’s Square, in the heart of Valletta, the co-cathedral of Saint John was commissioned in 1572 by Grand Master Jean de la Cassière. It was the conventual church of the Order of the Knights of Saint John, the Knights of Malta, built between 1573 and 1577-78 to a design by the Maltese architect Girolamo Cassar and consecrated on 20 February 1578. The front, austere and almost fortified, reflects the sober spirit of the Order in the period right after the Ottoman Great Siege of 1565. The interior, by contrast, was turned into a lavish Baroque masterpiece in the sixties of the seventeenth century by the Calabrian painter Mattia Preti, called by Grand Master Rafael Cotoner to decorate vaults and walls with episodes from the life of Saint John the Baptist, and later knighted a Knight of Grace by the Order itself. The floor of the nave is entirely covered with slabs of polychrome inlaid marble: the sources differ between about 378 and 405 of them, with the figure of «almost 400» the most commonly quoted. They commemorate knights and officers of the Order with heraldic arms, Latin inscriptions and memento mori images such as skeletons, skulls and hourglasses. Ground-penetrating radar surveys carried out in recent years have, however, identified only three burials actually confirmed beneath the floor, a sign that many slabs are commemorative rather than true tombs. In the Oratory of the co-cathedral hangs «The Beheading of Saint John the Baptist» by Caravaggio, painted in 1608: the largest work the painter ever made and the only one he ever signed, with his signature written in the blood flowing from the neck of the Baptist. Caravaggio had reached Malta in July 1607, fleeing Rome after killing Ranuccio Tomassoni in May 1606, and was knighted a Knight of Grace by Grand Master Alof de Wignacourt on 14 July 1608. Caught up in a brawl that gravely wounded a senior knight on 18 August of the same year, he was imprisoned in Fort Saint Angelo, from which he escaped to Sicily in early October, and was finally expelled from the Order on 1 December 1608 with the formula «a foul and rotten member». Contrary to a widespread rumour, the painting was not stolen in 1798: in that year the troops of Napoleon, after the surrender of the Order, plundered gold, silver and jewels from the treasury of the co-cathedral to fund the Egyptian campaign, but the paintings, already put in safety, were not touched. A real theft of another work by Caravaggio kept here, «Saint Jerome Writing», took place instead on New Year night of 1984, with recovery in 1987. The church, which in the nineteenth century obtained the status of co-cathedral, according to some sources in 1816 by a bull of Pope Pius VII and according to others in the twenties of the nineteenth century, has shared the episcopal seat since then with the cathedral of Saint Paul at Mdina. During the heavy air raids of 29-30 April 1941, in the siege of Malta in the Second World War, the building was damaged, the sources differing on how badly, between «slightly» and «gravely, almost destroyed», but the works of art had already been moved to safety elsewhere and no losses were recorded. On 30 November 1955 an unexploded German bomb of 900 kilos, nicknamed «Hermann», was found right in front of the co-cathedral during sewer-laying works and defused by a Royal Navy diver, averting what the sources describe as the probable destruction of the entire front.