When Italy was unified in 1861, there were no regions, while provinces and comuni existed in the former Italian states. Some form of grouping provinces appeared in the late 19th century with the term of compartimenti which in 1912 was replaced by the term regioni. Italy introduced regions into its jurisdiction with the Constitution that entered into force on January 1, 1948, which in articles 114 and 115 stated: "The Republic is divided into Regions, Provinces and Comuni."
At that time, the compartimenti of Friuli and Venezia Giulia were merged into the Friuli-Venezia Giulia region and Abruzzo and Molise merged into the "Abruzzi and Molise" region, which in 1963 was again split into the two regions of Abruzzo and Molise, bringing the current number of regions to 20.