Louis Prang, a 19th-century German immigrant to the United States, made an important contribution to Christmas in popular culture by:

Prang was a Bavarian-born lithographer who settled in Boston, Massachusetts in the 1850s and established a successful printing business.  He invented a way of reproducing color oil paintings, the "chromolithograph technique", and created a card with the message "Merry Christmas" as a way of showing it off.  He went on to produce a series of popular Christmas cards.  By 1881 he was printing more than five million cards annually.