A white stone building in old Delhi’s central market district may not seem too different from any of the other neglected structures lining a street crammed with electronics shops selling adapters, copper wire, X-ray films, electrocardiogram jellies—except for a small plaque out front. Bhagirath Palace, it informs passersby, was once the opulent residence of one of India’s most powerful women: a courtesan turned mercenary turned diplomat turned queen.

Begum Samru was the supreme commander of 3,000 troops, including at least a hundred European mercenaries, in 18th-century northern India. She held court, wore a turban, smoked a hookah, converted from Islam to Catholicism, and dubbed herself Joanna, after Joan of Arc. Yet, she is largely forgotten today, and Bhagirath Palace is one of only two physical markers of her existence in the country’s storied history.

"Women are not regarded as entitled to wield power directly," says Uma Chakravarti, noted historian and feminist. She is alluding to the women who occupy 78 of the 543 seats in India’s Parliament. Women in powerful positions today must work under the shadow of the men at the helm of political parties. But, Chakravarti says, “Begum Samru was able to use the moment of political transition to insert herself within those corridors of power and negotiate a space for herself." (Discover how Amazonian women smoked pot, got tattoos, killed—and loved—men.)

View Images This painting of Begum Samru and her household was done around 1830. The supreme commander of 3,000 troops, including many European mercenaries, she held court, wore a turban, smoked a hookah, and converted from Islam to Catholicism. Photograph by The Picture Art Collection, Alamy

That political transition was a period of upheaval and chaos in the 1700s as the Mughal empire that ruled the vast Indian subcontinent faced insurrections from local chieftains, as well as invasion and colonization by the British.

Begum Samru was born in 1750 with the given name Farzana. Some historians claim she was the daughter of a Muslim nobleman; others contend that she was an orphan raised in a kotha—a traditional Indian house of pleasure and debauchery where women danced for rich men.

To suppress mutinous local wannabes, Mughal kings hired European mercenaries—including Walter Reinhardt, from Austria, who earned the sobriquet Butcher of Patna after he killed 150 Englishmen there in 1763.

The married, 45-year-old Reinhardt was smitten by 14-year-old Farzana, whom he’d noticed in a kotha. The pair teamed up and formed a power couple: mercenaries for hire.

Farzana charmed the Mughal rulers in their courts. They anointed her Begum, a title of reverence. A morphed version of Le Sombre—Reinhardt’s nickname, for his somber demeanor—lent her a new surname: Samru. Had she been married to Reinhardt, the historian Aditi Dasgupta notes, Begum Samru wouldn’t have had access to the inner workings of the politics of the rulers and their courts. Marriage would have put the courtesan behind the bars of purdah, of gender segregation.

“She did not adhere to the traditional perception of women as self-sacrificing; instead, she did whatever was necessary to survive as a ruler,” says Archana Garodia-Gupta, author of the recent book, The Women Who Ruled India: Leaders, Warriors, Icons.

After Reinhardt’s death, Begum Samru—all four feet eight inches of her—commanded an army and ruled over the kingdom of Sardhana, a Mughal stronghold 85 miles northeast of Delhi, for five decades. Mughal kings summoned her when they were attacked by rivals. She had an ever-ready army and a knack for forging deals with anyone who attacked the Mughals. One Mughal emperor gave her the title Zeb-un-nissa (Ornament Among Women).

Begum Samru was, in the words of Julia Keay, one of her biographers, the “only emancipated Indian female most of these foreign acolytes would ever meet. They hung on her every word as she told of an age few could recall, of armies and atrocities, gallantry and treachery.”

Her adventures extended beyond the court. She chose one European lover after another, even making a suicide pact with a secret French lover. When the two of them were fleeing an attack, Begum Samru stabbed herself. The Frenchman shot himself when he saw her blood-soaked clothes. He died, but she survived. A spurned Irish lover—a dockworker turned mercenary—rescued her, and after his death, Begum Samru took care of his wife and children.

Garodia-Gupta’s book chronicles the lives of 20 women who have largely been left out of India’s history texts. It features Begum Samru’s diplomacy with the Mughals and the British. After Reinhardt died, she converted to Catholicism and built the Basilica of Our Lady of Graces, in Sardhana, with an Italian officer in her army as its architect.

“She knew that the British would be the rulers in future, and one could assume that her religious conversion was to appease to them. Or, maybe she truly found her path in being a Catholic,” Garodia-Gupta says.

“She never ate in the presence of her guests, and accounts vary as to whether she ever touched the wine... but when the memsahibs withdrew, she gestured to a servant to bring her hookah and then settled down to a companionable smoke amid the men and their cheroots,” Keay wrote.

Begum Samru died in January 1836. The East India Company, Britain’s imperial agent in India, inherited her fortune—approximately 55.5 million gold marks, one of the grandest Indian fortunes of the time, equivalent to an unimaginable 40 billion dollars today. She was buried under the basilica in Sardhana. An 18-foot-tall marble sculpture of Begum Samru—her torso draped in a shawl—towers near the altar.

Back in old Delhi at crumbling, soot-stained Bhagirath Palace, with its tall Greek columns, where male merchants dominate the trading scene, a lone old woman kept Begum Samru’s fire of defiance burning—albeit in her tiny medical supplies shop and not atop a throne.

“What do you want?” she snapped at me. “I have no time for you.”