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When was the North Atlantic Treaty signed?

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Flag of NATO featuring a white compass rose emblem with four lines radiating from the center on a blue background. — North Atlantic Treaty Organization Flag of the North Atlantic Treaty Organization (NATO).

The North Atlantic Treaty, also known as the Washington Treaty, was signed on April 4, 1949. This agreement established the North Atlantic Treaty Organization (NATO) as a collective defense alliance among 12 founding countries from North America and Western Europe to counter the influence of the Soviet Union following World War II.12