The question was how to keep the peace. And British Prime Minister Neville Chamberlain wanted peace. He had seen what war does. Had lost family to it. He knew the grief that settled into people as a result. So did many in Britain. The streets included men who walked with canes, their lungs scarred by gas, their faces by shrapnel. Women still wore black for sons who never came home. The Great War of just two decades prior had left its mark. The people didn't want another one. They wanted diplomacy.
On the other side stood Adolf Hitler. He wanted conquest. The Nazi leader had come to power in 1933, and in just a few years, he had already expanded Germany. First, it was the Rhineland, then Austria. No real fights. No real resistance. His publicly stated intentions ran much broader, though, and he had already set his next target: the Sudetenland region of Czechoslovakia.
Formed after World War I from the collapse of the Austro-Hungarian Empire, Czechoslovakia became home to over 3 million ethnic Germans in the Sudetenland. Hitler saw them as an ideal justification for Germany's expansion. Under the pretense of protecting German-speaking people, he stirred unrest in the region, fueling Sudeten German nationalist demands for separation. He promised to bring them into the Reich. By force if necessary. As he would say to Chamberlain in a conversation between the two,
"All this seems to be academic; I want to get down to realities. Three hundred Sudetens have been killed and things of that kind cannot go on; the thing has got to be settled at once: I am determined to settle it: I do not care whether there is a world war or not: I am determined to settle it and to settle it soon and I am prepared to risk a world war rather than allow this to drag on."
The 300 people that Hitler alluded to had not actually been killed. He fabricated the claim to justify increasing military pressure on Czechoslovakia and force Britain and France into negotiations.