WW1

Declaration of war with Mexico

May 12, 1846

{https://www.senate.gov/pagelayout/history/h_multi_sections_and_teasers/WarDeclarationsbyCongress.htm}

Assassination of archduke franz ferdinand

Jun 28, 1914

{https://www.history.com/news/the-assassination-of-archduke-franz-ferdinand}

Austrian-Hungarian declares war on Serbia

Jul 28, 1914

{https://www.loc.gov/law/help/digitized-books/world-war-i-declarations/foreign.php}

Austria-Hungary declares war on Russia

Aug 6, 1914

{https://www.loc.gov/rr/news/topics/ww1declarations.html}

First battle of Marne

Sep 6, 1914

{https://www.iwm.org.uk/history/10-significant-battles-of-the-first-world-war}