It is the famous "Ilinden" uprising. A month after that battle, leaders sent this http://dimobetchev.tripod.com/documents/ilinden.htm telegram to Sofia, Bulgaria, begging for Bulgarian schools top open in the region. Apparently because they were Bulgarians. They wanted to annex the region and Macedonia,Greece into Bulgarian state.
Anyway, the established government had members of all peoples of the region: Bulgarians, Albanians, Vlachs. Therefore the name "Rep of Kruchevo" is an excellent unifying name for the state and peoples that still are living in the Yugoslavian "Macedonia".