When the form carried into the early 19th century, its biggest influence was that it allowed:
Intimate psychological access → readers could directly see a character’s thoughts, emotions, and struggles.
Multiple perspectives → different letter-writers could narrate events from their own angle.
A sense of realism → letters and diaries made the story feel authentic, as if real documents were being read.
Moral and sentimental appeal → common in Richardson’s work, where readers “lived through” the heroine’s trials.
👉 So your statement is correct:
The epistolary novel influenced early 19th-century fiction primarily by offering intimate access to characters’ inner lives, paving the way for the psychological depth we see in later novels (like Austen’s free indirect discourse or the interiority of the Brontës).
