Religious themes and images have played a key role in Christmas cards since early on, and not just in the U.S. Since the first Christmas cards in the mid 19th century, and across the globe, religious greeting cards have featured angels, nativity scenes, Jesus and various other depictions commemorating the birth of Jesus.
Part of the diversity comes from the fact that different countries and cultures have different beliefs about the birth and different customs and traditions. Christmas is celebrated in different ways from country to country, as this site points out with a slew of rich examples:
“In Spain Navidad (Christmas) lasts nearly a month, beginning December 8th with the feast of the Immaculate Conception (the Virgin Mary is the patron saint of Spain) and ending January 6 with Epiphany. The season emphasizes religious rather than the secular traditions…”
“Italy, like Spain, emphasizes Nativity scenes and religious aspects of the season in its Christmas observances. People fast and pray prior to Christmas dinner. Epiphany is similarly the day for gifts, but the gifts are left by an elderly woman (La Befana) who had intended to help the wise men find the young Jesus — but had been busy cleaning. Children write letters to La Befana requesting toys..”
“In Russia “Babouschka” is the name of the elderly woman who failed to provide food & shelter to the Wise Men. She wanders searching for the Christ child, leaving gifts for children. Christmas dinner is a meatless meal eaten on January 6th (Christmas by the Julian calendar) following a period of fasting. In Ukraine the meatless Christmas dinner is served in twelve courses to honor the 12 apostles….”
People in the British West Indies have a Christmas celebration called Jonkonna, which is a combination of English mumming and African traditions. The festival involves elaborate costumes, music, dancing and mumming…”
The examples go on and on (see Wikipedia for more).
All of this created a rich array of religious cards from around the globe, each with its own personality. Below are examples of Polish Christmas cards, which I came across on Flickr, part of an amazing collection on this site
More recently, cards with the classic religious messages and images (like those below)) have been losing their popularity in many countries. This story from the UK based Daily Mail newspaper claims that in 2006, less than 1 percent of the cards sold in stores it surveyed were religious in nature. They’ve been replaced by cards with more modern religious and non-religious images.