Domenico Allegri (c. 1585 – 5 September 1629) was an Italian composer and singer of the early Baroque Roman School. He was the second son of the Milanese coachman Costantino Allegri, who lived in Rome with his family, and was a younger brother of the more famous Gregorio Allegri. Costantino sent three sons, Gregorio, Domenico and Bartolomeo,Perhaps Bartolomeo died at nineteen. See: Alberto Cametti, La scuola dei «pueri cantus» di S. Luigi dei francesi in Roma e i suoi principali allievi (1591-1623): Gregorio, Domenico e Bartolomeo Allegri, Antonio Cifra, Orazio Benevoli, Torino, Fratelli Bocca, 1915, p. 619. to study music at San Luigi dei Francesi, under the maestro di capella Giovanni Bernardino Nanino, brother of Giovanni Maria Nanino. The little boy had as schoolmate his elder brother Gregorio and then Antonio Cifra, Domenico MassenzioTo distinguish Domenico Allegri from Domenico Massenzio, the young pupils were mentioned as 'big Domenico' («Domenico grande» or «Domenico maggiore») and 'little Domenico' («Domenico piccolo», «Domenicucio» or «Domenico minore»). See also: Antonella Nigro, Domenico Massenzio. A new biography with unpublished documents, in Domenico Massenzio Opera omnia, Critical Edition by Claudio Dall'Albero and Mauro Bacherini, Vol. 1, Milano, Rugginenti, 2008, p. xxxvi. and Paolo Agostini.
