The beautiful and mysterious Princess Agnes Salm-Salm captivated East Coast society for a decade after 1861. She played a sometimes controversial, often conspicuous, and always colorful role in three of the century’s major events: the American Civil War, the fall of Maximilian’s empire in Mexico, and the Franco-Prussian War. An alluring American woman with an unknown past, she married a German soldier of fortune who served in the Union army and happened also to be a minor prince. Stories showed her alongside her husband in battle areas, treating the wounded and using her beauty and assertiveness to seek his professional advancement. Her exploits in Mexico included extravagant and verifiable efforts to save Maximilian from execution. As in the modern cases of Princess Grace of Monaco or Princess Diana of Great Britain, the contemporary fascination with this princess reveals something of the American desire for a paradoxical mix of aristocratic royalty with republican boldness.