The party was founded in 1921 when the Bolshevik-inspired maximalist faction won control of Romania's Social-Democratic party—the Socialist Party of Romania, successor to the defunct Romanian Social-Democratic Workers' Party and the short-lived Social Democratic Party of Romania (the latter was refounded in 1927, reuniting those opposed to communist policies). The establishment was linked with the socialist group's affiliation to the Comintern (just before the latter's Third Congress): after a delegation was sent to Bolshevist Russia, a group of moderates (including Ioan Flueraș, Iosif Jumanca, Leon Ghelerter, and Constantin Popovici) left at different intervals beginning with January 1921.