The Main Guard, originally called the Guardia della Piazza, is located in Valletta, across Grandmasters Palace. It currently houses the Office of the Attorney General.
The Main Guard building was built in 1603 as a guardhouse to house the Regimento di Guardia, the personal guards of the Grand Master of the Order of St. John.
In 1814, when Malta was under the rule of British Empire, a neoclassical portico and a relief of the British coat of arms above it was added to the Main Guard. The British continued to use the building to house the guards of the Governor of Malta, who resided in the Grandmaster's Palace. In the 1990s the Main Guard became an annex of the Office of the Attorney General.