Observatoire du temps 1 - La Rédemption de C. Colomb

From back cover Tor paperback February 1997:

In one of the most powerful and thought-provoking novels of his remarkable career, Orson Scott Card interweaves a compelling portrait of Christopher Columbus with the story of a future scientist who believes she can alter human history from a tragedy of bloodshed and brutality to a world filled with hope and healing.