Although pornography dates back thousands of years, its existence in the U.S. can be traced to its 18th-century origins and the influx of foreign trade and immigrants. By the end of the 18th century, France had become the leading country regarding the spread of porn pictures. Porn had become the subject of playing-cards, posters, post cards, and cabinet cards. Prior to this printers were previously limited to engravings, woodcuts, and line cuts for illustrations. As trade increased and more people immigrated from countries with less Puritanical and more relaxed attitudes toward human sexuality, the amount of available visual pornography increased.