Mint names began to appear on French coins under Pepin and became mandatory under Charlemagne. In 1389, Charles IV adopted a system called Secret Points. This scheme placed a dot under the first letter of the legend on coins of Crémieu, under the second letter for Romans, up to the twenty-second letter for Bourges. In the fifteenth century letters or symbols placed at the end of the legend indicating the mint were used in addition to Secret Points. In 1540, Francis I discontinued Secret Points in favor of a system of letters; A for Paris, B for Rouen, …, Z for Lyon; in the field. He also made it the rule for mint-masters to place their personal marks on coins, as they had done with increasing frequency since the coinage of Louis XI. This was one of the few royal practices continued by the Republic of France. The mint letters continued until 1898 (briefly revived in 1914 and from 1942–58) and the mint-masters marks, supplemented by the mark of the Chief Engraver, are still used.