One thing is certain about the French Revolutionary Wars, 1792–9: their effects far outran anything predictable from their causes. A war that everyone expected to end quickly dragged on with constantly changing combatants. The French started the war in a spirit of self-defence that rapidly morphed into a war of liberation and then a war of conquest and occupation. The other European powers entered the war to hold back the tide of revolution and soon found themselves defending their very existence as they watched the revolutionary tide flow and ebb and flow again, eroding every previous assumption made about the organisation of states and armies.