In order to maintain the balance of power in europe the "great powers", who met in sept 1814, agreed to meet periodically afterwards when trouble arose. what were these meetings called?

The correct answer is Austria, Britain, Prussia, Russia and France

France was not a part of it in the beginning but later joined and the Quadruple alliance became the Quintuple alliance, even though some countries like Britain had trouble ratifying it in their congress. They met a few times but ultimately it proved to be ineffective because wars eventually broke out again and their deals were annulled. 

Where are the following