Chain of events leading to WWI
1. Austria-Hungary advances ultimatum to Serbia on July 23, which is declined
2. Austria-Hungary attacks the Serbian capital of Belgrade on July 28
3. Russia backs Serbia and mobilizes on July 30
4. Austria-Hungary and Germany mobilize on July 31, while Germany demands Russia demobilise within 12 hours
5. Russia declines, Germany declares war on Russia on 1 August in support of Austria-Hungary
6. Austria-Hungary follows on August 6; France fully mobilizes in support of Russia on August 2
7. Germany demands free passage through Belgium, invades on August 4
8. Britain declares war on Germany on August 4
9. Britain and France declare war on Austria-Hungary on August 12