In the 16th century the Ming dynasty flourished over maritime trade with the Portuguese, Spanish and Dutch Empires. The trade brought in a massive amount of silver, which China at the time needed desperately. Prior to China's global trade, its economy ran on a paper money. However, in the 14th century, China's paper money system suffered a crisis, and by the mid-15th century, crashed. The silver imports helped fill the void left by the broken paper money system, which helps explain why the value of silver in China was twice as high as the value of silver in Spain during the end of the 16th century.