Question

After the assassination of the Austrian archduke, which happened first?

Germany invaded Belgium.
Great Britain invaded Germany.
Russia declared war on Serbia.
Austria declared war on Serbia.

Answer 1

Austria declared war on Serbia.

Russia and Serbia are allies, therefore, they did not go to war.

Germany invading Belgium happens AFTER Austria calls for Germany for back up. Same with Great Britain invading Germany.

Final Answer: Austria declaring war on Serbia happens after a Serbian citizen assassinate the Austrian archduke, catalyzing the beginning of the First World War