There is a theory that the earliest calling card, visiting card or business card was made by hand (manuscript) on the unprinted back of a playing card.
In my collection of secondary used playing cards I have a number of 18th and 19th century of those cards. Some might even be dating from the 17th century. See 12 examples attached. I only show the backs with text but all are done on playing cards. If you like to see the reverse side as well please contact me.
To save paper some cards are made on half a playing card or even a smaller part of a card. Please note that these calling cards on playing cards were not used by poor people. Some are used by noble men.
Are there any books or reliable studies about the history of calling cards and businesss cards?