Perosi first attended the Rome and Milan conservatories and thereafter (1893) went to Regensburg where he studied church music for a year under Franz Xaver Haberl on his return to Italy he wass appointed choirmaster of S Marco, Venice, and became an ordained priest in 1895. By 1898 his fame had spread and he was appointed music director of the Cappella Sistina. He was a deeply troubled man and growing psychological problems forced him to abandon his post in the Sistine Chapel 1915, by 1922 he was sufficiently mentally ill that he entered a mental hospital. He was declared cured in 1923 and resumed his position which officially he held until his death in 1956. But his recovery was far from complete and his frequent relapses ensured that his musical activities were at best intermittent. His music – especially his oratorios can be a bit eclectic and he was the first first modern Italian composer to be significantly influenced by pre-Classical music such as Gregorian chant and 16th-century polyphony. He's worth listening to if you stumble across his music, particularly his earlier music, as I did with the YouTube video below in which the Coro Vallicelliano di Roma perform his Pontifical Mass (Missa Pontificalis, per coro e organo) of 1897. Enjoy :-).