Franz Joseph I of Austria
His nephew Archduke Franz Ferdinand of Austria would have been his successor but he was assassinated.  Wars during the reign of Franz Joseph included the Second Italian War Of Independence (1859), the Austro-Prussian War (1866), the Third Italian War Of Independence (1866) and the 1899-1901 Boxer Rebellion.  He died during World War 1.  Charles I of Austria became emperor in 1916 and reigned from 1916-1918.