In 1794 the famous organ-builder Gaetano Callido (1727-1813) completely redid the organ present ab antiquo in the Grand Prioral Church, which had already been restored in 1685.
In 1843 thanks to the munificence of Archduke Fra’ Federico d’Austria-Teschen, Professed Knight of the Order of Malta, it was restored and enlarged by Angelo Agostini (1809-1890). A further restoration was carried out in 1958 with the addition of an electric fan.
The organ now has an unusual series of valuable registers and still preserves the eighteenth-century pipe theory.