The significant change came about when World War I began in 1914, and governments needed fast ways to issue money to finance military action – without being able to wait for gold production levels to increase. Before then, most countries had used the gold standard or a similar policy, but the limitations on gold mining could not keep pace with the growing scope and scale of international finance and trade demands. Central bank vaults could not validate the printing of more money, so governments changed to a fiat model to ensure flexibility around stabilising markets, financing spending, creating competition in export and import markets and setting independent monetary policies.