Answer: Munich Conference (September 29th and 30th, 1938)
The countries at this conference were: Britain, France, Germany, and Italy.
The Munich Conference is also known as the Munich Agreement.
The aim of the conference was to prevent a war from happening. In a sense, it did prevent a war, but it just gave Hitler the green light to take over whatever land he wanted. So it only delayed the inevitable.
World War II would start about a year later on September 1, 1939, when Germany invaded Poland.