If you’re going with traditional etiquette, a monogram is only for one person. It has three initials, the center initial is for the last name and is usually larger than the other two. The letter on the left is the first name initial and the letter on the right is the middle name initial.
The big scandal comes in when we get into married vs. single couples. Again, if you want to go traditional, there is no such thing as a combined monogram. The history of the monogram stems from back when royalty could rule a country without the prerequisite of being literate. (come to think of it, I’m not sure that is a prerequisite now). Back in the day not many people knew how to write their names. Royalty needed a way to mark proclamations and decrees, so they would design fancy logos using their initials and create an emblem which would be used to represent their signatures. Hence the single name. To give a traditional monogrammed gift to a married couple, such as towels or bathrobes, you would get two and put the man’s monogram on one and the woman’s married monogram on the other—sort of a fancy way of saying “his” and “hers”.
That brings us to the question of the married woman’s monogram. Before the wedding the monogram of a woman would be the same as above: first initial, last name larger, middle initial. However, once the woman gets married, she drops her middle name and her maiden name takes its place. Then the monogram becomes first initial on the left, married name initial larger in the center, maiden name initial on the right. In the case of a wedding invitation, the bride’s maiden name monogram should be the only one used. The married name monogram should not be seen until after the couple is actually married, usually on a thank you note (stay tuned for more wacky fun with thank you note etiquette in a future blog post.)
So why do we see so many combined initial monograms floating around on http://www.theknot.com/ and other wedding related sites? Because the modern idea is to throw out the etiquette of traditional format and do whatever you think works. Currently, combined monograms, while still technically incorrect, are being more widely accepted and used. (That still does not mean you can use it on a wedding invitation!) If you’re going to go with the new frame of mind on this, the bride’s first initial goes on the left (ladies first), the married name initial in the center, and the groom’s first initial on the right.
Many thanks to Margaret the Great for putting her stamp on this information. Visit her at her fabulous shop, Scriptura on Magazine St. in New Orleans or go online and check out their stock at http://www.scriptura.com/ Tell her I sent you :)