Excerpt from Leonardo's Swans by Karen Essex, plus links to reviews, author biography & more

In addition to her intellectual accomplishments, Isabella has tumbling blond curls, large, wide-set black eyes, and a slender body. Beatrice shows signs of stoutness, with thick thighs and ankles, though only her sister, her servants, and her husband--should the man to whom she is engaged actually honor their betrothal--will ever know this. She has a round face, a small, uninteresting nose, and dark hair that lacks luster, so much so that she must wear it in a long pigtail down her back. She prefers the outdoors to all pursuits. She is the kind of person Isabella would not find terribly interesting if she were not her sister.

Isabella consistently outperforms Beatrice in all pursuits but this, the equestrian. Now, and in the presence of her betrothed, Isabella fears Beatrice is trying to make her pay for her crimes of superiority.

Suddenly Francesco stops, pulling in the animal, whipping him about so that he is facing Isabella. She realizes that he is looking for her, has stopped this competition with her sister because she has entered his mind, even in the midst of the wild ride.

Beatrice, who has bolted ahead, stops too. No longer enjoying the ride without the competitive aspect, she trots back to him. Isabella hears Francesco say, "I wanted you to show me the city's newest improvements, not race me to your death."

"You just don't want to lose to a woman," Beatrice retorts, flushed scarlet from her escapade, adjusting the velvet cap that she wears at a clever tilt.

"Do you fail to remember that I was not losing?" he answers.

"Settle down," Isabella says in Beatrice's direction, hoping that she does not sound too much like the admonishing older sister, the sour one who does not want to be a part of their game. "We are supposed to be showing him the city!"

"Be a good girl, or I'm going to take Drago back home with me," Francesco says to Beatrice in a tone that conspires with Isabella's parental attitude toward her sister.

Beatrice clutches the reins close to her chest. "He wouldn't go. He would run away with me first!"

"Don't be too sure, little princess," he replies, sounding like a father.

Thank God he considers her a child and Isabella a woman! Satisfied that she can recapture Francesco's attention with her more mature demeanor, Isabella leads them over the bridge and back inside the city walls.

"Now, Beatrice, do listen to what I am telling Francesco so that when your betrothed comes to visit Ferrara, you might show him these same things."

Beatrice groans. The subject is a sore one.

Mistress once more of the little expedition, Isabella explains how the city of Ferrara has changed in recent years; how her father, the duke, had gotten it into his mind to rebuild the city along the enlightened architectural guidelines set by Leon Battista Alberti, the Genoan. She explains (to demonstrate her knowledge of not only architecture, city planning, and mathematics but political subtleties as well) how Ercole had sent to his ally, Lorenzo the Magnificent in Florence, for the ten manuscripts of Alberti's De Re Aedificatoria, to set about modernizing his city and its buildings according to that great theorist's vision. Streets were widened into broad avenues. New structures were created with careful attention to classical values of proportion and harmony. Aesthetics were linked with and equal to the mathematical proportions of things.

Excerpted from Leonardo's Swans by Karen Essex, pages 5-12.  Copyright © 2006 by Karen Essex. Excerpted by permission of Doubleday, a division of Random House, Inc. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.