Vienna Literary Agreement

The Vienna Literary Agreement (Serbo-Croatian: Bečki književni dogovor, Бечки књижевни договор) was the result of a meeting held in March 1850, when writers from Croatia, Serbia and Carniola (Slovenia) met to discuss the extent to which their literatures could be conjoined and united to create a standardized Serbo-Croatian language. The agreement recognized the commonality of South Slavic dialects and enumerated a basic set of grammar rules which they shared.

Source: Wikipedia — Vienna Literary Agreement (CC BY-SA 4.0)