It seems Santa was a bachelor until around 1849. The first mention of Santa Claus having a spouse was in a short story "A Christmas Legend" by James Rees, a Philadelphia Christian missionary. The story refers to an old man and woman, but doesn't mention the woman as being Mrs. Claus. The story is about a couple who are given shelter in a home on Christmas Eve. The next morning an abundance of gifts are left to the homeowners.
In 1851, Mrs. Claus is first revealed by name in the pages of the Yale Literary Magazine. The author names Mrs. Claus and portrays her helping Santa at a Christmas party. Later, Mrs. Claus is mentioned in an essay by Harper's Magazine dated 1862.
It wasn't until 1889, in a widely-circulated poem "Goody Santa Claus on a Sleigh Ride" by Katherine Lee Bates, that Mrs. Claus became popular. Since 1960, Mrs. Claus has gained many media appearances starting with the children's book, "How Mrs. Claus Saved Christmas" by Phyllis McGinley.
Mrs. Claus is generally portrayed as a white-haired elderly woman that is calm, kind, patient, and caring. Often, seen in the background of Santa, baking cookies and assisting him and the elves with the production of Christmas. The image is one of the earliest illustrations of Santa and Mrs. Claus shown on a postcard from 1919.