The Isla Parish Church, dedicated to the Birth of the Blessed Virgin Mary, was probably projected on a plan by the architect Vittorio Cassar in 1580 as a monument to the great victory of the Siege of 1565. It became a Parish at the beginning of the year 1581 and was consecrated on 20 October 1743 by Bishop Paolo Alpheran de Bussan. Pope Pius VI, on 21 May 1786 declared it Collegiate Insignia. In 1921 the church became a Basilica by decree of Pope Benedict XV and it also became a sanctuary because the statue of the Virgin Mary was crowned on 4 September 1921. In January 1941 it was destroyed by bombs but was rebuilt and was consecrated again by Mons. Mikiel Gonzi, Archbishop of Malta, on 24 August 1957.