ICSE Class 10 Answered
Archduke Francis Ferdinand, the heir to the throne of Austria-Hungary was assassinated at Sarajevo, the capital of Bosnia on June 28, 1914. The assassination was done by a secret society called ‘Black Hand’ or ‘Union of Death’. It was an organisation of extremist Serbian nationalists who wanted to unite all Serbians into a single Serbian State. As a result of the assassination, Austria served an ultimatum to Serbia on July 23 making eleven demands. Serbia accepted most of them, except those which would compromise her sovereignty.
As a response, Austria declared war on Serbia on July 28, 1914. Russia started preparations to support Serbia in the war. As a result, Germany declared war on Russia on August 1, 1914; and on August 3, on France. German troops marched into Belgium to press on to France on August 4 and on that day itself England declared war on Germany.
Hence, the assassination of Archduke Francis Ferdinand proved to be the immediate cause of the First World War.