M&M stands for Mars and Murrie. Forrest E. Mars Sr. was the founder of the Mars Company and Bruce Murrie was the son of Hershey Chocolate’s founder. The patented chocolate candies were created in 1941.
However, they were copied from Smarties, originally manufactured by British company H.I. Rowntree & Company in 1937. The lowercase Aachen SB-Medium font used on each candy made the candy unique and became a pop culture phenomenal success with clever ads.