Let us take a trip into history and move to 18'th century Anatolia. The province of Erzurum(a Turkish city) sends agricultural tax worth 1000 pieces of gold to the Imperial Treasury in Istanbul. Since the distance is considerable and road safety etc. is a real concern both the Treasury and the governor of Erzurum prefer alternative payment methods.

During a typical year, the animal growers of Erzurum send meat worth about 1000 pieces of gold to the butchers guild in Istanbul.(capital of Turkey)

Use your Money and Banking knowledge to devise a payment method so that the proceeds of the agricultural tax is received by the Treasury in Istanbul, WITHOUT actually transporting any gold, from Erzurum to Istanbul.