The newly formed Real union of Austria-Hungary lasted for the next half-a-century. The policies suppressing the National Revival in the Czech lands under the Austrian government continued, as well as the suppression of the Slovak National Revival under the Hungarian government. The end of the 19th century also was a time of a demographic boom and a rapid urbanization. Population in centers of industry doubled or tripled within a few decades. At the start of the 20th century, Austria's unilateral annexation of Bosnia in 1908 caused the Bosnian Crisis and prompted the eventual assassination of Ferdinand d'Este, sparking the World War I in 1914. Many of the Czech nationalists saw the war as an opportunity for gaining full independence from the Austria-Hungary. Desertion among the Czech conscripts was commonplace and Czechoslovak Legions were formed to fight for the side of Entente Powers. In the Cleveland Agreement of 1915, the Czech and Slovak representatives declared their goal of creating a common state, based on the right of a people to self-determination. When the World War I ended in 1918, the Kingdom of Bohemia officially ceased to exist and a new democratic republic of Czechoslovakia took its place.