The time of the Song Dynasty (960-1279) brought about significant innovations. At the beginning of their reign, the magnetic compass was for the first time used for naval navigation. This greatly reduced the dangers of navigation, which is why long-distance trade experienced an upswing. This, again, required new means of payment, because soon the demand for copper coins could not be answered any more. The first paper money of all times was issued, and promissory notes and other forms of credits developed. In the second half of the 10th century, up to eight billion coins were annually produced in China.