Following a rapprochement between the two groups, and with the approval of the USSR, the DKP and FS formed a joint federation in 1921, known as the Communist Federation (Danish: "Kommunistisk Føderation"). However, the cooperation would be short lived. The federation split in 1922 following an attempted coup of the party's leadership, and for the next 18 months Denmark would have two parties calling themselves the Communist Party of Denmark (although only one was recognized by the Comintern.) The two parties were successfully merged once more in 1923, but inter-factional conflicts would continue for another 20 years.