After the Assassination of Archduke Franz Ferdinand in Sarajevo, the Hungarian prime minister István Tisza and his cabinet tried to avoid the outbreak and escalating of a war in Europe, but their diplomatic efforts were unsuccessful. Austria-Hungary drafted 9 million (fighting forces: 7.8 million) soldiers in World War I (over 4 million from the Kingdom of Hungary) on the side of Germany, Bulgaria, and Turkey. The troops raised in the Kingdom of Hungary spent little time defending the actual territory of Hungary, with the exceptions of the Brusilov Offensive in June 1916, and a few months later, when the Romanian army made an attack into Transylvania, both of which were repelled. In comparison, of the total army, Hungary's loss ratio was more than any other nation of Austria-Hungary. The Central Powers conquered Serbia. Romania declared war. The Central Powers conquered Southern Romania and the Romanian capital Bucharest. In 1916 Emperor Franz Joseph died, and the new monarch Charles IV sympathized with the pacifists. With great difficulty, the Central powers stopped and repelled the attacks of the Russian Empire.