He wrote 10 books, made thousands of glass-plate photographs, and was compared in stature to two earlier explorers, Henry Stanley and David Livingstone.
But just as quickly as William Edgar Geil rose to fame, he faded into oblivion after his death in 1925 at age 60.
There he would have remained were it not for a serendipitous turn of events involving a cache of memorabilia in a Bucks County barn and a chance e-mail to China.
Renewed enthusiasm for Geil has produced two tributes: a yearlong exhibit that opened this month at the Doylestown Historical Society, and a three-month display in Beijing last year to mark the centenary of his Great Wall trek.
"He was a classic American eccentric," said Arthur Waldron, a history professor and Great Wall expert at the University of Pennsylvania. "With a touch of genius."
Bought at auction
A bibliophile from Buckingham Township held the keys to the forgotten Geil epic.
In 1959, Walter Gustafson bought the contents of Geil's library at an estate auction after the death of his widow, Constance Emerson Geil. She had been so grief-stricken when he died that she locked away his possessions.
Gustafson stored more than 20 boxes of Geil's papers in his barn, including many of the tin bread boxes the explorer took on expeditions.
For almost 85 years, the material inside was "untouched by any other human hands," said Marilyn Gustafson Arbor, the collector's daughter and curator of the Doylestown exhibit.
Arbor and her siblings donated the collection to the historical society last year.
The gift was met with predictable puzzlement. "Everybody said, 'Who's William Geil?' " recalled Timothy Adamsky, a historian for the society.
Adamsky trolled the Internet for help. He came upon William Lindesay, a British author in Beijing and founder of International Friends of the Great Wall, a nonprofit dedicated to its preservation.
Like Geil, Lindesay had written a book about traveling the Great Wall - which is not one wall but several, with some sections dating to the 5th century B.C.
In an e-mail, Adamsky offered to "share any knowledge . . . that Geil may have hidden in the boxes."
Lindesay was shocked. For a decade, he had searched for Geil's records, reaching out to his original London publisher, to the Library of Congress, the Smithsonian Institution, even the State Museum of Pennsylvania.
Everywhere he turned, nothing.
Both Geil and Lindesay had traversed the same Great Wall route - the best-known Ming Wall section - that starts in the northeastern coastal city of Shanhaiguan and ends in the western desert in Jiayuguan.
Lindesay made his trek in 1987, but learned of Geil's journey and his 1909 best-seller, The Great Wall of China, only years later. Intrigued by their parallel lives, Lindesay set out to re-photograph Geil's images.
Last summer, Lindesay went to Doylestown to see the Geil collection for himself.
There were thousands of newspaper clippings, maps, letters, and receipts, including one from a Shanghai tailor for two tweed jackets and silk pajamas.
There were pocket-size notebooks, with jottings of dates and places, and reminders to send photos to hosts.
There was a traveling kit with a handmade American flag, a pocket watch, and eyeglasses, and tin containers including ones marked "North China" and "Corea."
Lindesay borrowed items for an exhibit to mark the 100th anniversary of Geil's Great Wall trek, held last October at Beijing's Imperial College. It featured 80 "before and after" photographs by Geil and Lindesay, which were published in The Great Wall Revisited (2008). In some modern images, the Wall has been reduced to rubble; guard towers that Geil once viewed have disappeared.
"His photos preserve, in many places, a Wall that is no longer there," Lindesay said. "He was the father of Great Wall studies."
Took only photos
How was it that an explorer so celebrated in his day could slip from history?
One theory: Unlike his contemporaries, Geil came home with only pictures. He did not loot temples or tombs. He did not leave with armloads of antiquities.
Hence, his name was not immortalized on a museum wing or university collection.
"I like to think of my grandfather as one of the early people who believed you take nothing but photos, leave nothing but footprints," said the Rev. John Laycock, whose mother was adopted by Geil's childless widow after the explorer's death.
Born on a farm in New Britain Township, Bucks County, in 1865, Geil was a Baptist preacher, motivated by religion to explore the world.
He made six journeys, the longest and farthest being his "Great World-wide Tour" from 1901 to 1904 to investigate foreign missions and preach. In Melbourne, Australia, he spoke before 8,000 people at a revivalist meeting.
Geil financed trips by writing books and giving talks. He did not disappoint. The British Monthly enthused that his "oratory would kindle the dullest imagination."
Photos show Geil wearing a floor-length goat-skin coat next to his palanquin, a chair hoisted by poles on the shoulders of Chinese porters.
And sitting astride a water buffalo in the Philippines.
And firing a rifle in East Africa to summon natives to church.
Of his trip to Fiji, Geil recounted visiting a Christian church on a site where "banquets of human flesh [had been] of constant occurrence." In Congo, he vowed never again to ride the Aruwimi River rapids in a dugout.
He always traveled with an American flag. When he lost one, he had native helpers - a Pygmy boy of 13 in Africa or a laborer named Old Moon in China - make a new one. On the Yangtze, he wrote: "I doubted if ever before in the history of the Empire had a native gunboat passed these gorges and rapids flying the Stars and Stripes."
Wherever he went, he delighted natives with his aluminum Blickensderfer portable typewriter and carbon paper.
And his shoes.
"The size amazed them," wrote the 6-foot-2 Geil during a 1904 stop in China. "The heavy leather soles, the laces, everything, and of course the cost, were discussed."
Upon his return to Doylestown from the Great Wall in 1909, The Inquirer noted the "satisfaction that a Pennsylvanian has brought so much light to bear upon a dark spot on the map."
The silence of Geil's widow following his death also may have contributed to the cooling of his celebrity.
Daughter of a Sun Oil Co. founder, Constance was with Geil in Venice when he died of influenza. Rather than nourish his legacy, the bereaved widow sealed off his library in their 30-room Doylestown mansion and rarely spoke of him.
With the contents of that room revealed, the Doylestown Historical Society hopes to rescue Geil from obscurity.
Ed Ludwig, its president, said the goal was to elevate him to the status of Doylestown's other "greats": archaeologist and collector Henry Chapman Mercer, anthropologist Margaret Mead, author James Michener, and lyricist Oscar Hammerstein 2d.
"His legacy has not rivaled theirs," Ludwig said, "but his accomplishments as an explorer and an evangelist are almost beyond belief."
Contact staff writer Jennifer Lin at 215-854-5659 or firstname.lastname@example.org.
If You Go
"Dr. William Edgar Geil (1865-1925): Doylestown's Evangelical World Explorer"
Where: Doylestown Historical Society, 56 S. Main St., Doylestown; 215-345-9430
Hours: Saturdays 10 a.m. to 4 p.m.; Sundays noon to 4 p.m., or by appointment.
Admission: Free. Donations welcome.