Guidelines for Monograms
Although there have been periods in history when single initial monograms and two-letter monograms were preferred, the three-letter monogram has come to symbolize the standard layout.
In the 19th and Early 20th Centuries, when the rules for three-letter monograms were created, it would have been fairly easy to decide which letters represented which parts of an person's name.
Alice Canfield Bostwick would immediately recognize this monogram as her own – first name initial (A) on the left, middle name initial (C) on the right, and last name initial (B) in the center, larger than the rest.
For a married couple the man's initial goes on the right and the woman's initial goes on the left and of course the last name is in the center.
For a 2 initial monogram, as with any other monogram the woman's name always comes first.