13.) Europe's key economic problem in relation to the world trade network is defined as an "unfavorable balance of trade", meaning that it was buying...

13.) Europe's key economic problem in relation to the world trade network is defined as an "unfavorable balance of trade", meaning that it was buying more from Asia than it was selling (imports>exports). It was having to make up for the difference with gold which it had very little of. How did Europe, particularly Spain, solve that problem?