After the death of Kaiser Franz Josef in 1916, the Austrian Empire was left extremely weak under the reign of Karl (Charles) I. Karl was a meek ruler, unable to keep his country together, and riots broke out in the Slavic regions of Transylvania, Croatia, Slovenia, and the Muslim region of Bosnia, occupied in 1912. Transylvania, Croatia and Slovenia were violently put down, while Bosnia successfully gained its independence, mostly through the pressure that the Turks and Serbs put on Vienna. Austria's Airship fleet is roughly the equivalent of Britannia's, making it one of the largest in Europe.