Up to the early decades of the present century, Maltese music, or, better, music written by Maltese composers, was predominantly liturgical. The reason is simple: the only significant patron for Maltese composers was Malta's Roman Catholic Church. This was a consequence of the Church's own requirements of music for use in its sacred rites. These demand music of the highest and the most expressive order; for music in worship is, first of all, an uttering to the One who is worshipped. It is indeed a remarkable tribute to its perceptive faculty that the Maltese church was able to select the finest and most-gifted Maltese composers to be its maestri-di-cappella. One of them was Carlo Diacono.

Born at Zejtun on April 1,1876, into a middle-class musical environment where the church was one of the most palpable realities of childhood, Diacono exhibited from his early years a determined inclination towards the profession of church musician, in the mould of the legendary Maltese maestri-di-cappella of the 18th and 19th centuries. Whilst still young, he showed exceptional musical talent and, under the tuition of his father Orazio, learned to play proficiently the high clarinet, the piano and the organ. Between 1892 and 1902, he worked with PaolinoVassallo (1856-1923) who had studied in France with Jules Massenet and it was from him that he acquired the Gallic elegance that was, later on, to imbue such major compositions as Preghiera ala B. V. Maria (1924),Il Cantico di Frate Sole (1927), Laudate Pueri(1937), and Messa di Gloria in E flat(1938).

In 1899, Diacono was appointed organist of the Zejtun Parish Church, the first concrete appointment in the path he was destined to follow.

The promulgation, on November 22,1903, feast of St. Cecilia, Patron Saint of Music, of Pius X's Motu Proprio on church music, led to great upheavals in Maltese liturgical music which, in the hands of such maestri-di-cappella as Vincenzo Bugeja (1805-1860) and especially Paolo Nani (1814-1904), had become very operatic and extremely dramatic.

One of the first to conform to the Church's new regulations and compose liturgical music within the prescribed parameters was Paolino Vassallo. Vassallo's appointment in 1912 to the prestigious post of maestro-di-cappella to the Mdina and Valletta Cathedrals was a tangible sign of the Maltese Church's firm intentions to implement the Motu Proprio. In a contemporary environment, which was very ecclesiastical, the popularity of such gifted musician / composers as Carlo Diacono and Giuseppe Caruana (1880-1931), both students of Paolino Vassallo, who were also willing to compose liturgical music within the new dictates, increased. Many parish churches, especially in the southeast of Malta, engaged Carlo Diacono as their maestro-di-cappella and in order to be able to service them, he set up his own independent cappella (i.e. a group of male singers and instrumentalists who, under the direction of Diacono himself, performed his music in these churches).

Diacono's popularity and musical standing were enhanced when, following the death of Paolino Vassallo, he succeeded him as maestro-di-cappella at the same two Cathedrals on February 9, 1923. He thus achieved the highest possible position in his chosen profession.The number of parish and other churches who contracted him to supply music increased remarkably, and his cappella achieved a popularity which has had few equals in the annals of the history of church music in Malta.