The portion of Czechoslovakia, called the Sudetenland had a large German population. The Munich Agreement caused the annexation of this territory to the German nation.
When Germany invaded Poland, Britain and France had an agreement with Poland to come to Poland's aid should the country ever be invaded. As Germany refused to withdraw from Poland, Britain and France declared war against Germany.
The Munich agreement in 29 September 1938.
Poland. Germany had previously agreed in the Munich Agreement that if they were allowed to annex Sudetenland of Czechoslovakia they would not invade anywhere else. The Agreement was signed by Germany, Italy, Britain and France. Italy was allied with Germany so Britain and France declared war when Hitler invaded Poland in direct violation of the agreement.
The Munich Agreement .
The Munich Agreement was signed in Munich , Germany .
Initially they did not ally with Russia because Russia had allied with Germany. Once Germany attacked Russia and broke the pact the Russians wanted to ally with Britain and France. They eventually did.
france
Britain and France had a defence agreement with Poland. On 1 September 1939, German troops invaded Poland, so on 3 September 1939, Britain and France declared war on Germany.
Poland
Germany
Britain.
Andulusia