Giorgio Grognet de Vassé proposed rebuilding the church on a neoclassical design based on the Pantheon in Rome.

The residents of Mosta helped in building the church, taking part in construction work on Sundays and public holidays.

[7] During World War II, the town of Mosta was prone to aerial bombardment due to its proximity to the airfield of RAF Ta Kali.

However, one 50 kg (110 lb) high-explosive bomb pierced the dome and entered the church, where a congregation of 300 people [8] was awaiting early evening Mass.

[9][10][11] On 12 December 1973, Pope Paul VI issued a decree of canonical coronation of the titular painting of Our Lady of the Assumption that was crowned later on 10 August 1975, thereby elevating the church to the title of Marian Sanctuary.

[20] However, others praised the design, and an 1839 book written while the church was being built describes it as "certainly the most magnificent, extensive and solid modern building" in Malta.

This book further states that "when finished, [the church] will be an ornament to the Island, will immortalize the architect, and draw towards the casal every visitor to Malta.