In 1775, Charles Dumas designed the first diplomatic cipher that the Continental Congress and Benjamin Franklin used to communicate with agents and ministers in Europe. Dumas's system substituted numbers for letters in the order in which they appeared in a preselected paragraph of French prose containing 682 symbols. This method was more secure than the standard alphanumeric substitution system, in which a through z are replaced with 1 through 26, because each letter in the plain text could be replaced with more than one number.