Whether referred to as “Correspondence Courtship” or “Epistolary Courtship”, part of the natural course of 19th century courting included letter-writing. Victorian-era couples could express tender sentiments in letters more easily (often) than in person. Many couples didn’t have the opportunity to spend time together, face-to-face, for too many miles separated them. Coming to know one another, and fall in love, through letter-writing was a standard practice. Results varied from blissful conjugal felicity (a frequently used term of the American Victorian era) to sensational disasters.
Interestingly enough, the term “Correspondence Courtship” (or very similar phrasing) appeared much more frequently and earlier than did the phrase “Mail-Order Bride”.