- Franz Ferdinand, heir to the Austro-Hungarian throne, is assassinated by a Serbian nationalist in Sarajevo, Bosnia.
Russia's Support for Serbia:
- Russia, a Slavic ally of Serbia, offers its support to Serbia following the assassination.
Germany's Support for Austria-Hungary:
- Germany, allied with Austria-Hungary through the Dual Alliance, pledges support to Austria-Hungary.
Ultimatum to Serbia:
- Austria-Hungary issues an ultimatum to Serbia with demands that are considered to be harsh and unacceptable.
Serbia's Partial Acceptance:
- Serbia agrees to most of the demands in the ultimatum but hesitates on some points, leading to further tensions.
Declaration of War:
- Austria-Hungary, feeling disrespected by Serbia's partial acceptance, declares war on Serbia.
Russian Mobilization:
-Russia, sensing the threat to its ally, begins mobilizing its military in response to Austria-Hungary's actions.
German Ultimatum to Russia and France:
-Germany issues ultimatums to Russia and France, demanding they cease their military preparations or face war.
German Declaration of War on Russia and France:
- Russia and France do not comply with Germany's ultimatums, leading Germany to declare war on both countries.
Britain's Entry into the War:
- Britain, obligated by the Entente Cordiale with France, declares war on Germany in response to the violation of Belgian neutrality.
Escalation to World War:
- The initial conflicts between Austria-Hungary and Serbia, backed by their respective allies, escalate into a full-scale global conflict involving multiple nations, marking the beginning of World War I.