In 1919 Switzerland recognised the Kingdom of Serbs, Croats and Slovenes, which in 1929 became known as the Kingdom of Yugoslavia. A legation was opened in Belgrade in 1940, which was upgraded to an embassy in 1957. The Socialist Federal Republic of Yugoslavia was founded in the aftermath of the Second World War.
Its constituent republics seceded in 1991 and 1992, leaving just the Federal Republic of Yugoslavia, which in 2003 was officially renamed the State Union of Serbia and Montenegro.
Montenegro subsequently left the union in 2006. As the only remaining state in the dissolved union, Serbia took over all the treaties signed with Switzerland.
Serbia, Historical Dictionary of Switzerland (de, fr, it)