He co-founded the Partito dei Lavoratori Italiani in 1892 after renouncing his anarchist principles in 1879. It is probable that this happened due to his marriage to Russian Socialist Anna Kulischov. In his book My Years in Exile, Edward Bernstein wrote of the conversion: "When [ Filippo Marzotti ] first heard the news that Costa was lost to the Anarchist cause, he excitedly raised his hands above his head, and cried repeatedly, almost in desperation: 'Anna! Anna! Anna!'".
He died in Imola in 1910.
- Centenario della morte di Andrea Costa Biography, photographys etc. (Italian website)
- Edward Bernstein: My Years of Exile (Chap.2) at www.marxists.org