The Church of the Nativity, Jesus’s birthplace, gets its first repairs in more than 500 years

BETHLEHEM, West Bank — When Pope Francis arrives here Sunday on his first trip to the Holy Land as pontiff, he will enter the Church of the Nativity for private contemplation at the grotto believed to mark the birthplace of Jesus Christ. He may also notice that the church is falling apart.

The 1,700-year-old basilica is one of the oldest in Christendom, and the church is showing its age: The lead-covered roof leaks, the ancient rafters are rotting and water drips onto the 12th-century mosaics of hovering angels. So notorious is its decay that it was listed by the United Nations as an endangered world heritage site in 2012.

But in a kind of modern-day miracle, the three Christian denominations that share an acrimonious joint custody of the pilgrimage site — the Greek Orthodox and Armenian Apostolic churches and the Franciscan order of Roman Catholics — were persuaded by Palestinian Authority President Mahmoud Abbas to allow Italian master craftsmen, working alongside structural engineers and wood scientists, to perform the first major documented restoration since Venetian carpenters rebuilt the roof in 1479.

Pope Francis will get a look at the progress. After five years of study and debate, the first phase of work — fixing the sagging beams and replacing the bullet-pocked windows — is expected to be complete by Christmas, at a cost of about $3 million. The money was raised by the international community and dispersed by the Palestinians, so that none of the three caretakers can claim credit — or more rights — over the church. Renovations of mosaics, doors and paintings may follow if more funds can be secured.

On a recent sunny morning, Marcello Piacenti, a 53-year-old son of a family of Tuscan restorationists, scrambled up the scaffolding in a pair of Chuck Taylor sneakers to show a visitor the wooden rafters, which were fragrant with incense and rot.

“If this was your house, naturally, you might just want to replace the whole roof. But not here. The timbers are the church,” Piacenti said.

“We have to listen to each piece of wood and hear the story it tells us,” Piacenti said. “We have been surprised so many times to see what we have found here.”

IF THESE WALLS COULD TALK

Surprises include a hole left from a stray bomb that fell in the 1967 Middle East war, as well as sophisticated 6th-century seismic retrofitting that allows the roof, even today, to “float” during an earthquake.

Also: the amount of iron nails. About seven tons of them, some two feet long. Many are nearly as sharp as the day they were hammered into the wood.

To persuade the caretakers of the church to allow the repairs, the Piacenti family is performing the restoration while keeping the church open. Mostly, the carpenters work at night.

The original basilica, built in the 4th century by Roman Emperor Constantine, was leveled in the Samaritan Revolt of A.D. 529, though the floor mosaics survived. The church that stands today was constructed during the reign of Justinian in the 6th century.

It is built directly above a cave where tradition holds that Jesus was born to Mary and then laid in a manger because there was no place for them at the inn. Visitors who enter the church — after waiting in a long line outside what is one of the most popular Christian sites in the Holy Land — are herded along by monks to kneel at a subterranean altar and peer through a hole in a slab of marble to see the bedrock.

Over the centuries, the church has been besieged, burned, looted and shaken by earthquakes. It was transformed into a walled fortress by the Crusaders, who crowned their kings here.

The structure has also been beset by fungi, termites, sun, wind and rain. A Christmas storm last year dropped a foot of snow on the roof.

Qustandi Shomali, a professor at Bethlehem University, wrote a recent study of the physical state of the church, one of the most fought-over places in the Holy Land. He said “evidence of the turbulent history of the church can be readily seen in the fabric of the building.”

In 2002, during the second Palestinian uprising, dozens of Palestinian militants who were being chased by Israeli soldiers took cover in the church for 39 days. Restorers have found bullet holes in the windows, which are to be replaced with a special glass to reduce the ultraviolet rays reaching the medieval paintings below.

A DELICATE BALANCE

Piacenti lifted a cross-section of a roof beam, honeycombed with termite tunnels. The wood tells the story, he said.

The beam was constructed of larch. According researchers at the Trees and Timber Institute in Italy, the tree that it was carved from was felled in the high-altitude forests of the eastern Alps sometime between 1440 and 1460, and then floated down a network of rivers to Venice. There, it was put aboard a ship bound for what is now the Israeli port of Jaffa and then carried overland to Bethlehem.

That was the last fully documented restoration. Philip the Good, the Duke of Burgundy, paid for repairs, the Republic of Venice supplied the wood, and the carpenters and Edward IV of England donated the lead for the roof. The conservationists have also found evidence of more recent repairs: by Greek carpenters in the 1670s and by Ottoman-era workers after the earthquake of 1834.

Piacenti said each section of rafter, truss and tie-beam is examined microscopically and rated for its level of deterioration. Each repair requires a meeting of engineers, archaeologists and wood specialists. The craftsmen want to replace the bare minimum, but they also want their work to last a long time.

How long?

“If there is no water incursion, this wood should last forever,” Piacenti said. “Water is life, of course, but for the roof of the church it is death, because with water the wood comes back to life, and life in this case is decay.”

To replace larch beams, the restorationists have scoured markets selling ancient timbers — obviously a speciality niche — for beams of similar age that would have been salvaged from palaces and monasteries.

“We have bought 400 pieces, but only 50 are just right,” Piacenti said.

To repair a beam, they fit a new section of wood over the old, like a glove onto a finger, and reinforce the work with steel struts as if setting a broken bone. All the restoration work is done by hand, using tools and techniques that would have been familiar to the ship’s carpenters sailing with Christopher Columbus. They pull out the 500-year-old iron nails and reuse them.

Piacenti said he initially worried that the monks who serve as custodians of the church would bicker and fight. Famously, the priests once brawled because the Greeks, while dusting a chandelier, moved a ladder into the space reserved for the Armenians — a violation of a 200-year-old agreement to maintain a delicate status quo and do everything just as it has always been done.

So Piacenti and his workers have been very careful not to kick up too much dust.