Count Stefano Jacini of San Gervasio (3 November 1886 – 31 May 1952) was an Italian politician and historian, a leading figure of the Christian Democrats.

[3][4] Young Stefano was strongly influenced by Piero Martinetti, whose university lectures he attended, and by his spiritual mentor Ambrogio Ratti, the future Pope Pius XI.

After graduating, he contributed to a short-lived literary-religious magazine, it:Il Rinnovamento, along with it:Tommaso Gallarati Scotti, Alessandro Casati, Ajax Antonio Alfieri and Uberto Pestalozza.

[3][2] At the outbreak of the First World War he initially favoured neutrality but changed his view and supported the fight against Austria-Hungary as a means of completing Italian unification.

He hoped that Vittorio Emanuele III would lead the country in this direction and was among the 54 signatories of the message addressed to the king, on 6 June 1925, by the constitutional deputies of the opposition.

[3] Jacini took part in the attempt to return to the chamber on 16 January 1926; like the other deputies on that day, he was subjected to acts of violence by fascists, suffering an injury to his nose.

On 9 November he was declared to have forfeited his elected mandate, along with the other Aventine deputies, and this brought his political career to an end for the time being.

[3] During the referendum on the monarchy Jacini campaigned in favor of keeping it, however at the first party congress in Rome in April 1946, his position was clearly in the minority.