Originally named Socialists and Europeans (Socialisti ed Europei), the group was formed in 2006 as a faction within the Democrats of the Left (DS) by Gavino Angius and Giuseppe Caldarola in opposition to the creation of the Democratic Party (PD), which they believed would have been a rejection of the principles of social democracy and democratic socialism.
It was founded in April 2007 by those Democrats of the Left who supported the motion of Gavino Angius at the party last congress, but decided not to follow their leader in the Democratic Left and to participate to the foundation of the Democratic Party instead.
In October, after a consensual separation between the two groups and the foundation of the Socialist Party by Boselli, De Michelis, Craxi, Turci and splinters from Democratic Left (including Gavino Angius and Valdo Spini), the group of De Michelis changed name into Socialist Party (coherently with name of the future party), while the group of Caldoro retained the party's name and decided to change the symbol.