This imposing dome was originally a chapel built with funds provided by the Knight Fra Martino de Sarria in 1585. The original chapel was replaced in 1676 by a church dedicated to the Immaculate Conception. Grand Master Nicholas Cottoner built the church in thanksgiving for the end of the plague of 1675.
The rotunda was designed by the renowned painter Mattia Preti – who painted the vaults of St John’s Co-Cathedral in Valletta – and built under the direction of an equally renowned architect, Lorenzo Gafa’. This church is particularly striking for its pleasing proportions and the way it combines the baroque and classical tendencies of the time. The most precious possession of this church is the wonderful set of seven large canvases that surround the interior, painted by Mattia Preti.