The main difference is that a deposition includes a person’s thoughts and feelings, while historical fiction, such as Longfellow's poem "Paul Revere's Ride," includes made-up details.
A deposition is a legal procedure in which a witness provides sworn testimony about their firsthand experiences and observations, often conveying their thoughts and feelings about the events in question.
On the other hand, historical fiction incorporates elements of creativity and imagination, weaving fictionalized details into a narrative that is set against a backdrop of real historical events. While it may be based on factual occurrences, it does not adhere strictly to historical accuracy and often includes invented characters or events to enhance the storytelling.
So, while depositions focus on personal testimony, historical fiction blends fact with imagination.