When did the tradition of birthday messages on cards begin?

The tradition of sending birthday messages on cards started in ancient China. Europeans sent handmade paper cards as far back as the 15th century. Americans imported greeting cards from England until the mid 1800s, when German immigrant Louis Prang began producing them in Boston in 1875.

Prang, the "father of the American greeting card," created more than 5 million cards a year by 1881. The card industry boomed in the early 1930s with the successful development of color printing. Once sent to ward off evil spirits, birthday cards remain the most popular of all greeting cards, and they make up more than 60 percent of all card sales.