The Concert of Europe, also called the Congress System, was a system where the Great Powers of Europe maintained peace and prosperity for nearly one hundred years following the defeat of Napoleon in 1815. It was established by Great Britain, Austria, Prussia, and Russia, and later included France. In particular, the Austrian diplomat Metternich played a key role in starting the Concert.
Peace and security were maintained by careful management of the balance of power, so that when one country threatened to overwhelm the others, the remaining countries would band together in diplomatic and military alliances.
The Concert of Europe broke down in the lead-up to World War I.