Franz Ferdinand was the presumptive heir to the Austro-Hungarian Empire and was also known for his reformist attitude towards the governance of the empire. He was an advocate for both a federal system in the empire which would entail the creation of semi-autonomous states for the many ethnicities within the empire, and was also a proponent of Trialism, in which a third Croat-dominant slavic kingdom would be created within the Empire, essentially transforming the state into an Austro-Hungarian-Croat monarchy. Both plans undermined Serbian attempts at unifying the South Slavs under a Serbian banner, as the federal proposal would ideally pacify the south Slavs whose discontent was needed for a pro-unification movement and revolution, while a Croat-centered Slavic Kingdom would directly conflict with Serbia's own attempts at creating a Yugoslavian kingdom and would further entrench Bosnia's occupation by Austria-Hungary. Preventing these reforms from taking place by killing Franz Ferdinand was the primary goal of the assassins, and the World War that erupted as a result of the killing did ultimately allow for the creation of Yugoslavia.