Mentions of Mrs Claus appear to have begun in the early middle part of the 1800s, with her first mention in “A Christmas Legend“ by James Rees, and published in 1849, where she was referred to as Santa Claus’ “wife”.
In “Lill in Santa Claus Land and Other Stories” (1878) by Ellis Towne, Sophie May and Ella Farman, it is established that Mrs Claus is the one who writes in and maintains the Naughty/Nice list, with Santa peering out using a monstrous telescope to see who is behaving and misbehaving.