China gradually opened Tibet to tourists, only to close it during each stirring of civil unrest.

“A large element of Tibet’s historical allure grew precisely out of its isolation, that it was untouched by the modern world and did not welcome incursions,” Orville Schell, author of “Virtual Tibet,” a book about the enduring Western fascination with Tibet, wrote in an e-mail message. “So, there is a certain irony in the fact that China, which had been successful in removing a good deal of the allure of the Tibet mystique to Westerners by making it so accessible, now once again feels obliged to ‘close’ it.”

The history of Western attempts to penetrate into Tibet in the 19th and early 20th centuries is recounted in “Trespassers on the Roof of the World,” by Peter Hopkirk. The travelers often braved blizzards, mountain passes and marauding bandits, only to be stopped short of Lhasa by armies of Tibetans led by high-ranking monks. Sometimes they were taken prisoner and tortured. (I didn’t have it quite as bad on that mountain road. Not only did the paramilitary officers not draw weapons on us, they offered us hot milk as we sat in our car.)

In 1879, Col. Nikolai Prejevalsky of the Imperial Russian Army set out with an escort of armed Cossacks for the Tibetan capital, only to be halted within 150 miles of Lhasa by Tibetan officials. He turned back.

Eighteen years later, a British adventurer named A. Henry Savage Landor was captured on his way to Lhasa, brought to a provincial governor and tortured, including being stretched on a rack for 24 hours. After his release, he returned to England and wrote a best-selling book about his captivity.

Those who did make it into Lhasa usually did so in disguise. A handful of Indian spies in the employ of the British Empire posed as holy men. A Japanese Buddhist named Ekai Kawaguchi pretended to be a Chinese physician. And a Frenchwoman fluent in Tibetan language and culture, Alexandra David-Néel, became the first Western woman to set foot in Lhasa when she entered dressed as a pilgrim in 1923.

Image Credit... The New York Times

By then, though, news of Tibet had been seeping out into the world. That began with the British military expedition of 1904, led by Sir Francis Younghusband. With Maxim guns and Enfield rifles, the soldiers killed thousands of Tibetans on their march from India. The Tibetans were forced to sign a treaty with the British, one of the terms being that the British could post trade agents within Tibet. The British then did all they could to keep other foreigners out.