The Carthaginian or Punic shekel was typically around 7.2 grams in silver and 7.5 grams in gold (suggesting an exchange rate of 12:1). They were apparently first developed on Sicily during the mid-4th century BC. They were particularly associated with the payment of Carthage's mercenary armies and were repeatedly debased over the course of each of the Punic Wars, although the Carthaginian Empire's expansion into Spain under the Barcids before the Second and recovery under Hannibal before the Third permitted improving the amount and quality of the currency. Throughout, it was more common for Carthage's holdings in North Africa to employ bronze or no coinage except when paying mercenary armies and for most of the specie to circulate in Spain, Sardinia, and Sicily.