While there were several smaller Cossack detachments in the Wehrmacht since 1941, the 1st Cossack Division made up of Don, Terek and Kuban Cossacks was formed in 1943. This division was further augmented by the 2nd Cossack Cavalry Division formed in December 1944. Both divisions participated in hostilities against Tito's partisans in Yugoslavia. In February 1945, both Cossack Divisions were transferred into the Waffen-SS and formed the XV SS Cossack Cavalry Corps. At the end of the war, the Cossack collaborators retreated to Italy and surrendered to the British army, but, under the Yalta agreement, were forcibly repatriated with the rest of the collaborators to the Soviet authorities and some executed. (see Betrayal of the Cossacks) One of the Kuban leaders, the "ataman" Vyacheslav Naumenko served as their principle historian after World War Two, writing the first Russian language book about the Repatriation of Cossacks in his two volume work published in 1962 and 1970 entitled "Velikoe Predatelstvo" ("The Great Betrayal").