The Constitution of the Italian Republic (Italian: Costituzione della Repubblica Italiana) was enacted by the Constituent Assembly on 22 December 1947, with 453 votes in favour and 62 against. The text, which has since been amended 15 times, was promulgated in the extraordinary edition of Gazzetta Ufficiale No. 298 on 27 December 1947. The Constituent Assembly was elected by universal suffrage on 2 June 1946, at the same time as a referendum on the abolition of the monarchy. The Constitution came into force on 1 January 1948, one century after the Statuto Albertino had been enacted. Although the latter remained in force after Benito Mussolini's March on Rome in 1922, it had become devoid of substantive value.
If you want to go on a pilgrimage to the place where our Constitution was created go to the mountains where partisans fell, to the prisons where they were incarcerated and to the fields where they were hanged. Wherever an Italian died to redeem freedom and dignity, go there young people and ponder: because that was where our Constitution was born. — Piero Calamandrei
The groups that composed the Constituent Assembly covered a wide range of the political spectrum, with the prevalence of three major groups, namely christian democratics, liberals and leftists. All these groups were deeply anti-fascist, so there was general agreement against an authoritarian constitution, putting more emphasis on the legislative power and making the executive power dependent on it. So the Constitution doesn't follow the concept of separation of powers as conceived by major figures of the Enlightenment like Kant and Montesquieu, and incorporates mechanisms to protect the needs of governmental stability while avoiding any degeneration of parliamentarism.