He didn't. Britain declared war with Germany.
Germany didn't declare war in 1915 against anyone, it was actually Britain that declared war on Germany
Britain was the first to declare war on Germany and New Zealand and the rest of the commonwealth felt like they wanted to help britain defeat germany
To response to Germany invasion of Belgium.
1939
To response to Germany invasion of Belgium.
Because Germany invaded Poland.
yes
The 1939 invasion of Poland caused Britain to declare war on Germany, which started WWII.
Because of Germany's attack on Poland.
France and Britain had promised to declare war if Germany tried to obtain anymore territory. And they kept that promise when Poland was invaded.
3rd Sept 1939 in europ