Following the 2013 leadership election of the Democratic Party (PD), in which Matteo Renzi, a centrist, was elected secretary, an internal struggle arose within the party between Renzi's large majority (composed of "Renziani", assorted centrists and moderate social democrats) and the left-wing factions, which were very critical of Renzi, his government (2014–2016) and his proposed constitutional reform, which would eventually be voted down in a constitutional referendum in December 2016.