The Great Man's Lady(1941)

In Hoyt City, a statue of founder Ethan Hoyt is dedicated, and 100 year old Hannah Sempler Hoyt (who lives in the last residence among skyscrapers) is at last persuaded to tell her story to a 'girl biographer'. Flashback: in 1848, teenage Hannah meets and flirts with pioneer Ethan; on a sudden impulse, they elope. We follow their struggle to found a city in the wilderness, hampered by the Gold Rush, star-crossed love, peril, and heartbreak. The star "ages" 80 years.