The simple sober facade of St John’s gives no hint of its lavish interior. It was built as the conventual church of the Order and the Knights spent enormous sums of money embellishing the chapels of their languages.

The cathedral was built between 1572 and 1581 by Geralomo Cassar, and his training as a military engineer accounts for the sober exterior. Nearly a century later the prolific Italian artist, Mattia Preti, transformed Cassar’s severe interior into a glowing showpiece of baroque art. His greatest task, which occupied him for five years, was the decoration of the vault.