In July 1803, Jerome Bonaparte, Napoleon’s youngest brother, then serving as a naval officer, arrived in New York on leave. His brother’s fame opened every door. He called on President Jefferson in Washington; he went to a ball in Baltimore. There he met Betsy Patterson. When they danced, a chain on his tunic snagged her gown, and they became much taken with each other.

Speaking with unknowing prescience, Betsy declared she would rather be the wife of Jerome Bonaparte for one hour than of any other man for life. As for Jerome, his infatuation was immediate, importunate, and passionate, as only that of the shallow can be. When Betsy made clear the path to her bedroom ran through the chapel, they were married on Christmas Eve 1803 by Bishop Carroll, America’s ranking Roman Catholic ecclesiastic.

Napoleon ordered Jerome home. Jerome waited a year before sailing with Betsy in March 1805. At Lisbon, the French ambassador informed them that “Miss Patterson” could not enter France. Jerome persuaded Betsy to continue traveling while he worked things out with his brother. He promised to return and swore his love was eternal.

Napoleon threatened Jerome with imprisonment, having decreed the marriage null and its offspring illegitimate. When Betsy gave birth to a son, Jerome Napoleon Bonaparte, on July 7, 1805, Jerome hoped the news might mollify the emperor. Napoleon responded, “Your union with Miss Patterson is null and void in the eyes of both religion and the law.” This was not entirely true: The marriage was valid in America, and the pope would not annul it. But Jerome gave in, and Betsy returned to Baltimore after a negotiated settlement with Napoleon involving an annual pension of 60,000 gold francs.

The Treaty of Tilsit in 1807 created a new kingdom, Westphalia, from several German principalities. On August 8, 1807, Jerome became its king. Later that month, he married Princess Catherine of Wurttemberg. Jerome went to work – on party after party, ball after ball. An observer wrote, “He played at being king as little girls play at being grown-up women.”

In January 1814, the Allied powers drove Jerome from Westphalia, and his kingdom vanished as if it had never been. After Waterloo, he escaped to Wurttemberg, believing his father-in-law would welcome him. Instead, King Friedrich jailed Jerome for two years. Only after Catherine defied her father’s repeated orders to divorce Jerome did the king relent, exiling them to Italy.

After making a fortune in real-estate speculation, Betsy divorced Jerome by special act of the Maryland Legislature in 1815. She returned to Europe, where Talleyrand praised her wit; Madame de Stael, her beauty; Wellington, her spirit. In 1822, Betsy was in Florence’s Pitti gallery when Jerome and Catherine walked in. Betsy had last seen him in Lisbon 17 years before, when he had declared his undying love and promised to return. She gazed into Jerome’s face, and he looked away.

Jerome’s fortunes revived with the rise of his nephew, Louis Napoleon Bonaparte, who became Napoleon III in 1852. After Jerome died on June 24, 1860, he was entombed in the Invalides near Napoleon’s sarcophagus. Betsy’s suit for a share of his estate was dismissed by the French courts. She died in 1879, at age 94, leaving millions to her descendants. Betsy’s son declined Napoleon III’s offer of a title, replying that one who bore the name Bonaparte needed no other distinction.

He had two sons. The younger, Charles Joseph Bonaparte, was appointed secretary of the Navy by Theodore Roosevelt in 1905, which, he privately observed, seemed appropriate as grandfather Jerome had been a naval officer. As TR’s attorney general from December 17, 1906, to March 4, 1909, Bonaparte was renowned as “Crook-Chasing Charlie.” He died in October 1921.

The attorney general’s childless nephew would be the last American Bonaparte. Jerome-Napoleon Charles Bonaparte, born in 1878, was tall, slender, and mustachioed. A New Yorker throughout his adult life, his inherited wealth let him live as he pleased and do as he liked, and so he never held a job or practiced a profession. In 1921, he was informally offered the Albanian crown, as was Harry Sinclair, the multimillionaire oilman. He was interviewed during the intermission of the Lux Radio Theatre’s broadcast of Sardou’s “Madame Sans-Gene” on December 14, 1936.

Otherwise, as one historian wrote, his was “a singularly unspectacular life,” recorded in one-sentence society-page entries, such as “Mr. and Mrs. Jerome Napoleon Bonaparte are in Palm Springs” or newspaper photographs of him with his Brussels griffon at the Newport Kennel Club’s dog show.

Talleyrand observed that Napoleon’s death had not been an event: merely an item of news. Jerome-Napoleon Charles Bonaparte’s death was not even that: On November 10, 1945, while walking his wife’s dog in Central Park, he tripped over its leash and broke his neck.