Born Apr. 20, 1876, in Albano; died Apr. 12, 1942, in the city of Gorky, USSR. Prominent member of the Italian labor movement.
Gennari graduated from the mathematics department of the University of Rome and was a teacher. He joined the Italian Socialist Party in 1897 and was a leader of the party in Florence. One of the organizers of the maximalist fraction in 1917, Gennari was elected general secretary of the Italian Socialist Party in 1918 and led the group of left maximalists who fought for the expulsion of the reformists from the party. In 1919-20 he was one of the organizers of the movement in defense of Soviet Russia.
Gennari participated in the founding of the Communist fraction of the Italian Socialist Party and later, in 1921, of the Italian Communist Party (ICP). He was a member of the Central Committee of the ICP from 1921 to 1926 and a deputy to parliament from 1921 to 1922 and again from 1924 to 1926. Gennari vigorously fought against fascism. Following a party decision, he left Italy in 1926 and lived in Western Europe, Latin America, and the USSR. A delegate to the Third and Fourth Congresses of the Comintern, Gennari was a member of the Presidium of the Executive Committee of the Comintern from 1921 to 1922, a member of the Executive Committee from 1922 to 1924, and a member of the International Control Commission of the Comintern from 1924 to 1928.