was the first kingdom mentioned here, a part of any war?
Yes, Serbo-Bulgarian War
Kingdom of Serbia
The Serbo-Bulgarian War erupted on November 14, 1885, and lasted until November 28 of the same year. 
when was the croatian parliament formed? 19 April 1273 which is the country that it governs over? Republic of Croatia where is the parliament located? UNANSWERABLE where is the country mentioned above located? At the crossroads of Central and Southeast Europe on the Adriatic Sea. when did it become independent? 25 June 1991 which country ruled over it prior to that? Yugoslav People's Army which religions are practiced here? Christianity, Eastern Orthodoxy, rotestantism, and Islam who was behind the formation of the army mentioned above? UNANSWERABLE when was it formed? 1945 what was the country of the army known as historically? "Kingdom of Serbs, Croats and Slovenes"
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Kingdom of Serbia [SEP] Serbo-Bulgarian War, 1885
The Serbo-Bulgarian War erupted on November 14, 1885, and lasted until November 28 of the same year. The war ended in defeat for Serbia, as it had failed to capture the Slivnitsa region which it had set out to achieve. Bulgarians successfully repelled the Serbs after the decisive victory at the Battle of Slivnitsa and advanced into Serbian territory taking Pirot and clearing the way to Niš. When Austria-Hungary declared that it would join the war on the side of Serbia, Bulgaria withdrew from Serbia leaving the Serbo-Bulgarian border precisely where it had been prior to the war. The peace treaty was signed on February 19, 1886, in Bucharest.