San Crisogono
Ciriaci was born in Rome to Giuseppe Ciriaci and his wife Maria Giuggiolini Magnaterra. Baptized in the church of San Crisogono, he received his first Communion on 27 June 1897. Ciriaci entered the Pontifical Roman Seminary on 31 October 1902, and then studied at the Pontifical Roman Athenaeum S. Apollinare, where he obtained doctorates in philosophy (5 July 1904), theology (6 July 1909), and canon law (8 November 1911).