The Entente Powers[edit | edit source]

Note: The "Entente Powers" are also known as the Allies of World War I or the Allies

The Central Powers[edit | edit source]

Neutral countries[edit | edit source]

Declarations of war[edit | edit source]

European military alliances prior to the war.

Allies and Central Powers, early August 1914.

Allies and Central Powers, mid 1918.

The following table shows the timeline of the several declarations of war among the belligerent powers. Entries on a yellow background show severed diplomatic relations only, not actual declarations of war.

Date Declarer On
1914
July 28 Flag of Austria-Hungary (1869-1918).svg Austria-Hungary State Flag of Serbia (1882-1918).svg Serbia
August 1 Flag of the German Empire.svg Germany Flag of Russia.svg Russia
August 3 Flag of the German Empire.svg Germany Flag of France.svg France
August 4 Flag of the German Empire.svg Germany Flag of Belgium.svg Belgium
Flag of the United Kingdom.svg United Kingdom Flag of the German Empire.svg Germany
August 5 Flag of the Kingdom of Montenegro.svg Montenegro Flag of Austria-Hungary (1869-1918).svg Austria-Hungary
August 6 Flag of Austria-Hungary (1869-1918).svg Austria-Hungary Flag of Russia.svg Russia
State Flag of Serbia (1882-1918).svg Serbia Flag of the German Empire.svg Germany
August 9 Flag of the Kingdom of Montenegro.svg Montenegro Flag of the German Empire.svg Germany
August 11 Flag of France.svg France Flag of Austria-Hungary (1869-1918).svg Austria-Hungary
August 12 Flag of the United Kingdom.svg United Kingdom Flag of Austria-Hungary (1869-1918).svg Austria-Hungary
August 22 Flag of Austria-Hungary (1869-1918).svg Austria-Hungary Flag of Belgium.svg Belgium
August 23 Merchant flag of Japan (1870).svg Japan Flag of the German Empire.svg Germany
August 25 Merchant flag of Japan (1870).svg Japan Flag of Austria-Hungary (1869-1918).svg Austria-Hungary
November 1 Flag of Russia.svg Russia Flag of the Ottoman Empire.svg Ottoman Empire
November 2 State Flag of Serbia (1882-1918).svg Serbia Flag of the Ottoman Empire.svg Ottoman Empire
November 3 Flag of the Kingdom of Montenegro.svg Montenegro Flag of the Ottoman Empire.svg Ottoman Empire
November 5 Flag of the United Kingdom.svg United Kingdom
Flag of France.svg France
Flag of the Ottoman Empire.svg Ottoman Empire
1915
May 23 Flag of Italy (1861-1946) crowned.svg Italy Flag of Austria-Hungary (1869-1918).svg Austria-Hungary
June 3 Flag of San Marino.svg San Marino Flag of Austria-Hungary (1869-1918).svg Austria-Hungary
August 21 Flag of Italy (1861-1946) crowned.svg Italy Flag of the Ottoman Empire.svg Ottoman Empire
October 14 Flag of Bulgaria.svg Bulgaria State Flag of Serbia (1882-1918).svg Serbia
October 15 Flag of the United Kingdom.svg United Kingdom
Flag of the Kingdom of Montenegro.svg Montenegro
Flag of Bulgaria.svg Bulgaria
October 16 Flag of France.svg France Flag of Bulgaria.svg Bulgaria
October 19 Flag of Italy (1861-1946) crowned.svg Italy
Flag of Russia.svg Russia
Flag of Bulgaria.svg Bulgaria
1916
March 9 Flag of the German Empire.svg Germany Flag of Portugal.svg Portugal
March 15 Flag of Austria-Hungary (1869-1918).svg Austria-Hungary Flag of Portugal.svg Portugal
August 27 Flag of Romania.svg Romania Flag of Austria-Hungary (1869-1918).svg Austria-Hungary
Flag of Italy (1861-1946) crowned.svg Italy Flag of the German Empire.svg Germany
August 28 Flag of the German Empire.svg Germany Flag of Romania.svg Romania
August 30 Flag of the Ottoman Empire.svg Ottoman Empire Flag of Romania.svg Romania
November 1 Flag of Bulgaria.svg Bulgaria Flag of Romania.svg Romania
1917
July 2 State Flag of Greece (1863-1924 and 1935-1970).svg Greece Flag of the German Empire.svg Germany
Flag of Austria-Hungary (1869-1918).svg Austria-Hungary
Flag of the Ottoman Empire.svg Ottoman Empire
Flag of Bulgaria.svg Bulgaria
July 22 Flag of Thailand (1916).svg Siam Flag of the German Empire.svg Germany
Flag of Austria-Hungary (1869-1918).svg Austria-Hungary
Flag of the Ottoman Empire.svg Ottoman Empire
August 14 Flag of the Republic of China (1912-1928).svg China Flag of the German Empire.svg Germany
Flag of Austria-Hungary (1869-1918).svg Austria-Hungary
October 26 Flag of Brazil (1889-1960).svg Brazil Flag of the German Empire.svg Germany
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