After the final defeat of Napoleon in 1815, the victorious coalition established a set of alliances meant to preserve a territorial status quo and to protect the ruling royal families against democratic revolutions. In principle, all of Europe (including a rehabilitated France returned to the rule of the Bourbon family) was committed to common principles of security against the threat of war and social unrest, but over time it struggled to contain conflicts of interest among the powers. As the Ottoman Empire went into decline, the Balkans and Middle East became a theater for competition, leading to the Crimean War in 1854 in which the Great Powers of Europe went to war once more. Still, the main purpose of the Concert was to avoid general war, which it managed to prevent until the First World War in 1914.

Originating with the diplomat George Kennan, who used the term in his 1946 “Long Telegram” to the State Department offering an explanation of Soviet motives, containment came to describe the overall American strategy during the Cold War. Rather than accommodate the Soviet Union, and appease its penchant for expansionism, or seek to roll back Soviet gains in Eastern Europe and run the risk of nuclear war, the US used containment as a moderate approach that aimed to check Soviet ambitions in areas of vital interest while waiting for the flaws within their own system to manifest.