African currency was originally forme from basic items, materials, animals and even people available in the locality to create a medium of exchange. This started to change from the seventeenth century onwards (though there is still some slavery), as European colonial powers introduced their own monetary systems into the countries they administered. As African countries achieved independence through the twentieth century, some retained the new denominations that had been introduced, though others renamed for various reasons. Today inflation often creates a demand for more stable (but forbidden) foreign currency, while in rural areas the original bartering system is still in widespread usage.