Fiat made wars more affordable, prior to that, countries tended to war until the money ran out and then had to have peace. Once war became both affordable and deadlier, countries had to spend more money during peacetime as they built themselves up again. Central banks therefore were in a better position to make sure that all combatants were better timed for maximum profit. It can't be a coincidence that wars since the Central Bank system came into being, have had more combatants and a wider battlefield - Wars are very profitable for banks particularly if they play all sides off against each other on a regular schedule. The development of the atomic bomb probably delayed the third world war by a considerable bit as the bankers couldn't make a profit from a nuked world...