How did the assassination of Duke Franz Ferdinand plunge European countries into the first world war? ?
Franz Ferdinand was an Archduke of Austria-Este, Prince Imperial of Austria and Royal Prince of Hungary and Bohemia, and from 1896 until his death, heir presumptive to the Austro-Hungarian throne. His assassination in Sarajevo precipitated Austria-Hungary’s declaration of war against Serbia. This caused countries allied with Austria-Hungary (the Central Powers) and countries allied with Serbia (the Triple Entente Powers) to declare war on each other, starting World War I.