United Kingdom declaration of war on Germany (1939)
E187837
The United Kingdom declaration of war on Germany in 1939 was the formal announcement by the British government that it was entering World War II in response to Germany’s invasion of Poland.
All labels observed (1)
| Label | Occurrences |
|---|---|
| United Kingdom declaration of war on Germany (1939) canonical | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T1657254 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.
NED1
Entity disambiguation (via context triple)
gpt-5-mini-2025-08-07
Target entity: United Kingdom declaration of war on Germany (1939) Context triple: [British Expeditionary Force (World War II), mobilizedAfter, United Kingdom declaration of war on Germany (1939)]
-
A.
Invasion of Poland
The Invasion of Poland was the 1939 German and Soviet military campaign that triggered the start of World War II in Europe.
-
B.
German attack on Westerplatte
The German attack on Westerplatte was the opening military engagement of World War II in Europe, where German forces assaulted a Polish military transit depot near Gdańsk in early September 1939.
-
C.
United Kingdom military operations in Europe
United Kingdom military operations in Europe encompass the various campaigns, interventions, and peacekeeping missions conducted by British armed forces across the European continent, particularly during and after the World Wars and the Cold War.
-
D.
Gleiwitz incident
The Gleiwitz incident was a staged 1939 false-flag attack by Nazi Germany on a German radio station, used as propaganda to justify the invasion of Poland and the start of World War II.
-
E.
Hitler’s Reichstag speech of 1 September 1939
Hitler’s Reichstag speech of 1 September 1939 was the address to the German parliament in which he announced and attempted to justify the invasion of Poland, marking the beginning of World War II in Europe.
- F. None of above. chosen
- G. Unsure - the case is ambiguous/there is not enough information to decide.
NED2
Entity disambiguation (via description)
gpt-5-mini-2025-08-07
Target entity: United Kingdom declaration of war on Germany (1939) Target entity description: The United Kingdom declaration of war on Germany in 1939 was the formal announcement by the British government that it was entering World War II in response to Germany’s invasion of Poland.
-
A.
Invasion of Poland
The Invasion of Poland was the 1939 German and Soviet military campaign that triggered the start of World War II in Europe.
-
B.
German attack on Westerplatte
The German attack on Westerplatte was the opening military engagement of World War II in Europe, where German forces assaulted a Polish military transit depot near Gdańsk in early September 1939.
-
C.
United Kingdom military operations in Europe
United Kingdom military operations in Europe encompass the various campaigns, interventions, and peacekeeping missions conducted by British armed forces across the European continent, particularly during and after the World Wars and the Cold War.
-
D.
Gleiwitz incident
The Gleiwitz incident was a staged 1939 false-flag attack by Nazi Germany on a German radio station, used as propaganda to justify the invasion of Poland and the start of World War II.
-
E.
Hitler’s Reichstag speech of 1 September 1939
Hitler’s Reichstag speech of 1 September 1939 was the address to the German parliament in which he announced and attempted to justify the invasion of Poland, marking the beginning of World War II in Europe.
- F. None of above. chosen
Statements (48)
| Predicate | Object |
|---|---|
| instanceOf |
World War II event
ⓘ
declaration of war ⓘ diplomatic event ⓘ |
| alsoInvolved |
Commonwealth of Nations
ⓘ
Dominions of the British Empire ⓘ |
| announcedBy | Neville Chamberlain ⓘ |
| announcedFrom | 10 Downing Street ⓘ |
| announcedTo |
British public
ⓘ
international community ⓘ |
| broadcastMedium | radio ⓘ |
| category |
1939 in the United Kingdom
ⓘ
Declarations of war ⓘ United Kingdom in World War II ⓘ |
| concurrentWith | French declaration of war on Germany (1939) ⓘ |
| conflict | World War II ⓘ |
| country | United Kingdom ⓘ |
| date | 1939-09-03 ⓘ |
| declaredOn |
Germany
ⓘ
Nazi Germany ⓘ |
| followedUltimatumTo | Germany ⓘ |
| government |
UK government
ⓘ
surface form:
Government of the United Kingdom
|
| hasChronologyRelation |
Invasion of Poland
ⓘ
surface form:
German invasion of Poland
Soviet occupation of Eastern Poland ⓘ
surface form:
Soviet invasion of Poland
|
| historicalPeriod | 20th century ⓘ |
| historicalRegion | Europe ⓘ |
| languageOfAnnouncement | English ⓘ |
| legalBasis |
Polish–British Common Defense Pact
ⓘ
surface form:
Anglo-Polish military alliance
|
| location |
London, England
ⓘ
surface form:
London
|
| monarchReigning | George VI ⓘ |
| officeHolderAnnouncing |
Prime Minister
ⓘ
surface form:
Prime Minister of the United Kingdom
|
| partOf |
British response to the invasion of Poland
ⓘ
outbreak of World War II in Europe ⓘ |
| politicalContext |
appeasement policy crisis
ⓘ
end of interwar period ⓘ |
| precedes |
Battle of France
ⓘ
Battle of the Atlantic ⓘ Phoney War ⓘ |
| reason |
Invasion of Poland
ⓘ
surface form:
German invasion of Poland
German refusal to withdraw from Poland ⓘ violation of Polish independence ⓘ |
| result |
beginning of British military operations in World War II
ⓘ
state of war between the United Kingdom and Germany ⓘ |
| subjectOf |
documentary films
ⓘ
historical research ⓘ history books ⓘ |
| time | 11:00 BST ⓘ |
| ultimatumReason | demand for German withdrawal from Poland ⓘ |
| year | 1939 ⓘ |
How these facts were elicited
The pipeline generated the facts above by prompting gpt-5.1 with this entity's name + description and the instruction below.
Instruction
You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10. # Requirements - If you don't know the subject at all, return an empty list. - If the subject is not a named entity, return an empty list. - Include at least one triple where predicate is "instanceOf". - Do not get too wordy. - Separate several objects into multiple triples with one object.
Input
Subject: United Kingdom declaration of war on Germany (1939) Description of subject: The United Kingdom declaration of war on Germany in 1939 was the formal announcement by the British government that it was entering World War II in response to Germany’s invasion of Poland.
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.
British Expeditionary Force
→
mobilizedAfter
→
United Kingdom declaration of war on Germany (1939)
ⓘ
subject surface form:
British Expeditionary Force (World War II)