Balkan Crisis:

• Austria-Hungary vs. Russia: tension over Balkans
• Assassination of Archduke Franz Ferdinand
• German "blank check" (full support) for Austria
• Austrian ultimatum to Serbia (humiliating demands refused)

Declarations of War: Eastern Front

• Austria declared war on Serbia July 28, 1914
• Partial (later full) mobilization of Russian army
  European mobilization plans generally inflexible
• German ultimatum to Russia: stop mobilization within 12 hours
• Germany declared war on Russia August 1

Declarations of War: Western Front

• Schlieffen Plan: defeat France first (through Belgium)
  Holding action/redeployment to east against Russia
• Germany declared war on France August 3
• Violation of Belgian neutrality rights
• Great Britain declared war on Germany August 4