The Boselli government of the Kingdom of Italy held office from 18 June 1916 until 30 October 1917, a total of 499 days, or 1 year, 4 months, and 12 days. It was a national unity government, composed of the Liberal Party (PL), the Italian Radical Party (PRI), the Italian Catholic Electoral Union (UECI), and the Italian Reformist Socialist Party (PSI), that dealt with World War I following the Italian entry into World War I in 1915 and the early spread of the Spanish flu that officially became pandemic in 1918. As the Italian Socialist Party (PSI) had largely remained at the opposition and only at times gave external support at most, the Boselli government was notable for the first participation of part of the socialists through the PSRI.