RESTORING the tomb of 17th-century scientist and scholar Xu Guangqi to a fitting 21st-century memorial was a bit like a meticulous crime scene investigation.

The “scene” in question was a disintegrated tomb site and the “crime” was the passage of time that obliterated public records of a man once called the “Francis Bacon of China.”

The tomb park, which includes the newly reopened Xu Guangqi Memorial Hall, is accessed across an arched stone bridge with ornamental columns and then under an archway etched with cranes. An 80-meter stone path, flanked by a row of stone tigers, sheep and horses, leads to a white marble cross and the burial mounds for Xu, his wife, his four grandsons and granddaughters-in-law.

For Shanghai Jiao Tong University Professor Cao Yongkang, creating the proper resting place for a hero of Shanghai’s past began 14 years ago, with only several archive photos and a few relics to work from.

“From a panorama taken from the Xujiahui Observatory early last century, I figured out major elements of the tomb, including ornamental columns, the memorial archway and the burial mounds,” says Cao, who spent half a year digging up a few photos taken at tomb ceremonies in 1903 and 1933.

There were no original drawings of the tomb site.

Xu’s death in 1633 was mourned by the last Ming Dynasty Emperor Chongzhen. He provided an imperial grant to bury the esteemed scientist and scholar in 1641 in what is today Xujiahui.

In 1903, at ceremonies marking the 270th anniversary of Xu’s death, the Shanghai Catholic Church added a white-stone cross to the tomb site. Thirty years later, at another memorial ceremony, eminent scientists, scholars and politicians paid tribute to Xu.

But after the Japanese occupation of Shanghai beginning in 1937, the tomb sank into oblivion. During the “cultural revolution” (1966-76), it was destroyed, with only a 2.2-meter-high mound of grass marking the site.

Glutinous rice and brown sugar

Like a CSI technician, Cao had to autopsy what was left of the site and pore meticulously through archive materials to determine how it once looked. He found snippets of information in books, records and old newspapers.

He also interviewed Xu’s descendants, who grew up near the tomb, and studied the tombs of other prominent Ming officials, such as the Suzhou tomb of Sheng Shixing, a powerful minister during early years of the dynasty.

“Xu’s descendants recalled five burial mounds, which were later combined into a single larger one when the site was turned into a park in 1979. They also remembered gingko trees near the mounds, cloud patterns on column bases and railings circling the cross,” Cao says.

During the restoration work, a shovel accidentally hit upon a broken brick from the tomb. The mortar joint of the brick contained semi-transparent crystals that made the joint even stronger than the brick itself.

“The crystals were glutinous rice, according to ancient Chinese wisdom,” Cao explains.

“The ancient Chinese added certain organic ingredients to inorganic building materials,” he adds. “The ground bricks in Beijing’s Forbidden City were painted with China wood oil, so they remain solid until today. We discovered a lime concrete harder than ordinary concrete when surveying the famous Tulou (earthen buildings) in Fujian Province. Guess what the locals put into the lime? Brown sugar.”

The small archway

Xu’s tomb area originally covered 1.5 hectares, but nearby construction encroached on the site. While it may lacks the grandeur of more famous tombs, like Sheng’s gravesite in Suzhou, Xu’s tomb exudes the peaceful beauty of a small environment surrounded by pine, maple and camphor trees.

Cao was questioned whether he had miscalculated size of the original memorial archway, the tomb’s highlight at the entrance. He ended up recreating it on a smaller scale.

“Fortunately, we found a few remnants from the original archway at the site and several photos from the 1950s,” Cao explains. “With the help of photographic surveying, which was used on a Chinese historical building for the first time, we transformed the photos to a 3D model of the archway, so I’m 100 percent sure of its size.”

The small scale of the archway signaled that Xu was an honest official in his ministerial roles, free from corruption.

“It took eight years for his family to finally bury him, implying a tight budget,” Cao says.

Xu was a convert to Catholicism, and the white marble cross placed at his gravesite by the Shanghai Catholic Church was also restored, using a historical photo from historian Zheng Zu’an as a guide.

“People often ask why a cross appears at this ancient Chinese tomb,” says Song Haojie, former deputy director of the Xuhui District Cultural Bureau and an advocate of the restoration project. “The inscriptions under the cross tell how Xu fought for the foreign missionaries who were mistakenly attacked by some Ming officials and how local Catholics donated to build the cross in 1903.”

To a younger generation, Xu is an unknown figure of history. The memorial hall, 100 meters east of the tomb, offers them an interactive introduction to the scholar’s life and achievements.

There, visitors can “plant” sweet potatoes — just like Xu did to feed starving masses — via a multimedia cartoon, and they can see a model of the rotations of the sun, moon and earth.

“Every year, Xu’s descendants came here from around the world to pay homage to their ancestor,” says Huang Xinhua, director of the memorial hall.

The restoration project won a municipal award, but Cao says he would do it differently if he were embarking on the project today.

“With today’s technology, I could inlay the original remnants in the archway to show differences between original and the restored parts,” he says, adding that the remnants are now on display on the grasslands of the tomb park.

“Back in 2002, it was widely accepted that a demolished historical building needed to be recreated according to its original look,” he says. “But any restoration, even if it’s 100 percent loyal to the original, is still not authentic.”

Former director Song says the restored tomb will help raise the profile of this important figure in Chinese intellectual history.

Professor Cao says he learned a lot from Xu while restoring the tomb.

“His accomplishments, from translations to scientific research, were all rooted in his strong enthusiasm,” Cao says. “That was the Shanghai spirit — a willingness to accept new things and contribute to China’s development in a practical way.”