13/02/1920 The League of Nations formally recognizes Swiss neutrality
Why is Switzerland always Neutral ?
Switzerland and Neutrality - WW2 War Stories
Switzerland was not invaded during either of the world wars. Swiss neutrality was seriously questioned by the Grimm–Hoffmann Affair, but it was short-lived. Switzerland joined the League of Nations, which was based in Geneva, on condition that it was exempt from any military requirements.