Winding beneath the magnificent halls of St. Petersburg’s Hermitage Museum, with its Da Vincis, diamonds, Greek statuary, Egyptian parchments, enormous number of paintings, mechanical peacock clock, and other treasures, there is a catacomb of cellars. It was into this windowless nether region—far below the Winter Palace’s expansive view of the waters of the Neva—that Maria Haltunen and I had cautiously descended. As I followed her through a narrow, imperfectly-lit corridor, full of large pipes and jutting wires, Haltunen gasped. “Look!” she said.

In the semi-darkness, a little being had appeared. He perched, a foot-tall shadow, on a water pipe.

“Oh, you are a fat one!” said Haltunen, jangling the chain of her I.D. pass like a talisman as she approached the pointy-eared creature. “How nice you are!”

The cat sat, perfectly still. Then he vanished.

“Some of them like to be around people,” said Haltunen, who has been the personal assistant to the museum’s director for the last eighteen years and, in addition to her regular duties, also serves as the museum’s semi-official Press Secretary to the Cats. She peered behind the pipes to see where the creature had gone, but found only a blanket, tucked against the wall, and a bowl. “Some of them prefer to be by themselves.”

Once a motley crew of frightened strays hiding, half-starving, in the palace’s basement, the Hermitage’s cats are now a well-loved, well-fed part of the museum’s family. Some seventy former street cats live at the Hermitage, where, thanks largely to Haltunen’s efforts, they have their very own underground cat infirmary and three full-time volunteers to care for them.

Underground, in their domain, there were signs of them—tiger-striped cat beds, bright pink and blue plastic bowls, places where the heating system’s pipes had been covered in soft, flowered material so that the cats could nest there. Now and then, a pair of bright eyes glanced out from a shaft; in a fenced-off corner, beneath blue and red water pipes, sprawled a little black kitten with white paws. As we passed, he jumped up, sprightly, and sidled out of the off-limits area.

“Our director is always saying they are the spirit of the place,” said Haltunen. “The museum’s genius loci.”

It wasn’t always this way. Fifteen years ago, Haltunen came upon the cats, sheltering in beleaguered prides in the museum’s heating system. Troubled by the animals’ plight, she and a colleague started feeding them, donning maintenance uniforms and lugging leftovers from the cantina to do the rounds of the extensive basements each day after work. “It was awful, after working all day, to put on ugly clothes, to carry stinky beans through these dark basements,” said the diminutive Haltunen, who, with her large, bright eyes and button nose is not entirely un-catlike, herself. “But if you start, you can’t stop.”

Then, they decided to organize. They took up a collection—“A rouble for a cat”—and used it to buy food. Newspaper articles appeared. People became interested. The museum’s director gave them permission to use some little rooms in the basement to keep ill and elderly cats, and hooked up running water. “You know how it is,” said Haltunen, “You see a problem, and then you have to do something.”

In theory, the cats now form a fanged, clawed army with one goal: to catch and kill mice who might want to chew on the artworks. In practice, “they are fat and lazy,” said Haltunen, with evident pride. (A security guard once took a picture of one looking on, in astonishment, as a rat drank from his bowl of milk.) Still, according to Haltunen, when an exterminator came, they found fewer rat corpses afterwards than usual. She says that the mere presence of the cats, their bodies and smells, serves as a deterrent.

There have been cats in the palace since Peter the Great’s daughter, Empress Elizabeth, issued a decree, in 1745, that the biggest cats, capable of catching mice, be sent immediately from Kazan to the court of her imperial majesty. Catherine the Great is thought to have favored Russian Blues as indoor palace cats; under the last Czar, the royal family’s pet cats, who were left behind in the palace, fared better than the dogs, who were taken along to Yekaterinburg with the family to their deaths. During the three-year siege of Leningrad, all of the animals in the city died—except for the rats, said to have been so numerous as to form a gray, moving mass in the streets. When the blockade was lifted, Haltunen said, as we continued our walk beneath the museum, Russians sent their cats to the city to help fight the vermin.

Stepping into the little cat hospital, a cozy, cluttered space that the oldest and sickest cats call home, Haltunen greeted Irina Popovetz, one of the volunteers who looks after the cats. Then she greeted Kusya (“Oh, this one has no tail!”), Jacqueline (“Look how fat we are!”), Sofiko (“You are very old!), and Assol, a tabby named for an impoverished literary heroine who waited at the seaside for a man sailing a ship with scarlet sails to come for her.

Taking a seat in the warm, pungent room and stroking Sofiko, she explained that, thanks to in part to donations from the German society Pro Animale and the pet-food company Purina, there is now an official Hermitage “cat account”—which always in the black. However, the cats are not just charity cases: last year marked the first official “Catfest,” in which all the entries for a contest for the best cat painting (there were nearly three hundred, mostly submitted by children) were exhibited for a day in the basement. For the second annual Catfest, held this spring, a scavenger hunt for children in the museum led to the museum’s only cat mummy, put on display that day only. Catfest was so popular that there is talk of extending it to two days next year. “We were astonished,” said Haltunen. “Crowds come to our dirty basement! It is really popular.”

The cats themselves, who are no longer afraid of people, have a positive effect on staff morale, she said. “People here become kinder, because they have the possibility to show this kindness,” said Haltunen, as we made our way back outside, where an orange cat was asleep in the sun beneath a classical statue. “It is very good when you have the possibility to show your best qualities.”

While cats are not allowed in the galleries or in the museum director’s wing, the people-loving felines have free rein in the former apartments of the ladies-in-waiting, where staff offices are now located. In the deputy of security’s office, “Little Hooligan,” a kitten abandoned in the countryside, where a security worker saved her from being used to train someone’s dog, was drinking milk under the Xerox machine. Frida, a black cat found in the garbage, posed on top of the bookshelf like a nineteenth-century Parisian lithograph, though—according to the photographic evidence that was immediately produced—she still likes to sleep in plastic bags. Niko, who looks like a mini-tigress, was fast asleep on a desk, with her tongue out (the desk’s putative owner assured us that this was no problem: grabbing hold of the sleeping cat’s long, bushy tail, the woman said that whenever she needed to sign anything, she just dips the tip in ink).

“People from Western countries, they say unfortunately they cannot permit cats in their offices,” said Haltunen, looking around, contentedly. “We are very lucky here.”

Photograph by Dmitry Lovetsky/AP.