The unification of Italy gradually assimilated the independent states which had been issuing stamps since 1850. The Kingdom of Italy was proclaimed on 17 March 1861 and the first Italian stamps were issued 24 February 1862 which were similar in design to those issued by Sardinia in 1855 but perforated. The first complete issue inscribed “Poste Italiane” was released on 1 December 1863 and was printed in both Turin and London. After World War I, Italy gained territory from Austria, particularly in the area of the Tyrol (Trentino) and Venezia Giulia. Stamps for these areas were issued on 11 November 1918.
As Germany's ally, Italy declared war on 10 June 1940 and the following wartime period saw a tremendous array of overprinted and uniquely designed occupation stamp issues. Invaded by the Allies on 3 September 1943 prolonged action continued throughout the war. British, American and other Allied forces Post Offices continued to operate until 1945.
On 17 September 1943 stamps for the Allied Military Government were issued in Sicily; further issues were released for use in Naples. The Royal Italian Government was re-established. At that time control of the southern regions was transferred to them by the Allies and the stamps of Italy issued prior to this date were used. On 23 September 1943 Mussolini proclaimed the Italian Social Republic which administered those parts of Italy which were occupied by Germany. Overprinted stamps for this area were issued in February 1944.
In June 1944 King Victor Emmanuel abdicated in favour of his son Umberto, who became Regent and then King of Italy. On 10 June 1946 a republic was formed and Umberto abdicated. The first stamps of the republic were issued on 31 October 1946. We highly recommend the stamp listings in the Stanley Gibbons Part 8 “Italy & Switzerland” also the various excellent specialised catalogues published by Sassone.