Communist Party of Slovakia
ZKS emerged from the Communist Refoundation Platform of KSS ("Platforma komunistickej obnovy KSS", PKO), a faction formed inside the Communist Party of Slovakia (KSS) in 1990. In March 1991 PKO formed ZKS as a new party. ZKS was registered with the Ministry of Interior of the Slovak Republic in Bratislava on March 19, 1991.