On 30 September 1938, Germany, Great Britain, France and Italy signed the Munich Agreement. As a result, the northern, southern, and western parts of Czechoslovakia, known as Sudetenland, were ceased to Third Reich.
Czechoslovakian authorities were informed by Britain and France that they could either allow the annexation of their teritory or resist on their own. They chose to submit.
The Munich Agreement was a failed attempt at appeasing expantionist intentions of Nazi Germany as it did not prevent neither the annexation of the rest of Czechoslovakia in March 1939 nor the beginning of the Second World War marked by the invasion of Poland on 1 September 1939.