The use of what is now the latter day female marriage-neutral honorific “ms”, has been traced as far back as the mid-eighteenth century, when it was used as an abbreviation for “miss” or “mistress”.
Ever since “Ms.” emerged as a marriage-neutral alternative to “Miss” and “Mrs.” in the 1970s, linguists have been trying to trace the origins of this new honorific. It turns out that “Ms.” is not so new after all. The form goes back at least to the 1760s, when it served as an abbreviation for “Mistress” (remember Shakespeare’s Mistress Quickly?) and for “Miss,” already a shortened form of “Mistress,” which was also sometimes spelled “Mis.”