Betty Zane. by Zane Grey

Betty Zane, published in 1903, was Zane Grey's first novel. It tells the romanticized story of Grey's great-great-aunt, who made a miraculous dash under fire to save a frontier fort from Indian attack. Fort Henry sat on the site of present-day Wheeling, West Virginia. One of a series of fortifications built to protect frontier settlers, it was commanded by Colonel Ebenezer Zane, and was the center of a small community where Colonel's brothers and his sister Betty lived.
The fort survived two sieges by Native Americans, first in 1777 and again in 1782. In the 1782 siege the attacking tribes were joined by British soldiers ; and it is this siege, and the events leading up to it, that are recounted in Betty Zane. Grey claimed to derive the facts in his story from the personal notebook, preserved in his family, of his great-grandfather Ebenezer Zane, but it's impossible for readers to distinguish historical fact, the supposed contents of the notebook, and the Grey's own imagination.
Certainly some aspects of the tale, like Betty's romantic involvements, are entirely fictionalized. But equally certainly, other major aspects of the tale, in particular Betty's heroism during the siege, come straight from the pages of history.