Feature Articles - Who Declared War and When
The 'Great War', which
began on 28 July 1914 with Austria-Hungary's
declaration of war with Serbia, was the first truly global war. It
began in Europe but quickly spread throughout the world. Many countries became
embroiled within the war's first month; others joined in the ensuing four
years, with Honduras announcing hostilities with Germany as late as 19 July
1918 (with the record going to Romania, who entered the war - albeit for the
second time - one day before it finished, on 10 November 1918).
Detailed below is a list of the nations who formally declared hostilities during World War One, along with their date of entrance. Nations of the British Empire, e.g. Australia, Canada and New Zealand, automatically entered the war with Britain's decision to enter the fray on 4 August 1914.
Note that on numerous occasions hostilities were assumed without a formal declaration, e.g. Russia with Germany and Austria-Hungary in August 1914.
Australia
Entered war together with Britain on
4 August
1914
Austria-Hungary
Declared war with Serbia on
28 July
1914
Declared war with Russia on
6 August
1914
Declared war with Belgium on
28
August 1914
Declared war with Portugal on
15 March
1916
Belgium
Invaded by Germany on
3 August
1914
Bolivia
Severed relations with Germany on
13 April
1917
Brazil
Severed relations with Germany on
11 April
1917
Declared war with Germany on
26
October 1917
Bulgaria
Declared war with Serbia on
14
October 1915
Declared war with Romania on
1
September 1916
Canada
Entered war together with Britain on
4 August
1914
China
Severed relations with Germany on
14 March
1917
Declared war with Germany on
14
August 1917
Declared war with Austria-Hungary on
14
August 1917
Costa Rica
Severed relations with Germany on
21
September 1917
Declared war with Germany on
23 May
1918
Cuba
Declared war with Germany on
7 April
1917
Ecuador
Severed relations with Germany on
8
December 1917
France
Invaded by Germany on
2 August
1914
Declared war with Austria-Hungary on
12
August 1914
Declared war with Turkey on
5
November 1914
Declared war with Bulgaria on
16
October 1915
Germany
Declared war with Russia on
1 August
1914
Declared war with France on
3 August
1914
Declared war with Belgium on
4 August
1914
Declared war with Portugal on
9 March
1916
Greece
Declared war with Austria-Hungary on
27 June
1917
Declared war with Bulgaria on
27 June
1917
Declared war with Germany on
27 June
1917
Declared war with Turkey on
27 June
1917
Guatemala
Declared war with Germany on
23 April
1918
Haiti
Declared war with Germany on
12 July
1918
Honduras
Declared war with Germany on
19 July
1918
Italy
Declared war with Austria-Hungary on
23 May
1915
Declared war with Turkey on
21 August 1915
Declared war with Germany on
28 August 1915
Declared war with Bulgaria on
19 October 1915
Japan
Declared war with Germany on
23 August 1914
Declared war with Austria-Hungary on
25 August 1914
Liberia
Declared war with Germany on
4 August
1914
Montenegro
Declared war with Austria-Hungary on
5 August
1914
Declared war with Germany on
8 August 1914
Declared war with Bulgaria on
15 October 1915
New Zealand
Entered war together with Britain on
4 August
1914
Nicaragua
Declared war with Austria-Hungary on
8 May 1918
Declared war with Germany on
8 May 1918
Panama
Declared war with Germany on
7 April 1917
Declared war with Austria-Hungary on
10 December 1917
Peru
Severed relations with Germany on
6 October 1917
Portugal
Entered war against Germany on
9 March
1916
Entered war against Austria-Hungary on
15 March
1916
Romania
Declared war with Austria-Hungary on
27 August 1916
Exited war with
Treaty
of Bucharest on
7 May 1918
Re-entered the war on
10 November 1918
Russia
Declared war with Turkey on
2 November 1914
Declared war with Bulgaria on
19 October 1915
San Marino
Declared war with Austria-Hungary on
3 June 1915
Serbia
Declared war with Germany on
6 August 1914
Declared war with Turkey on
2 November 1914
Siam
Declared war with Austria-Hungary on
22 July 1917
Declared war with Germany on
22 July 1917
Turkey
Declared war with Romania on
30 August 1916
Severed relations with United States on
23 April 1917
United Kingdom
Declared war with Germany on
4 August 1914
Declared war with Austria-Hungary on
12 August 1914
Declared war with Turkey on
5 November 1914
Declared war with Bulgaria on
15 October 1915
United States of America
Declared war with Germany on
6 April 1917
Declared war with Austria-Hungary on
7 December 1917
Uruguay
Severed relations with Germany on
7 October 1917
Reference:
Funk & Wagnalls New Encyclopedia, Volume 27,
Funk & Wagnall, 1983
A 'Woolly Bear' comprised a German shrapnel shell, which burst with a cloud-like explosion.
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