ROME — Paolo Violini climbed the steps on his knees.
“See, it’s not difficult,” Mr. Violini, a restoration specialist at the Vatican Museums, said as he slowly shimmied up the frescoed stairwell leading up to a once-private papal chapel in Rome. Granted, it was an unusual way to climb a set of stairs. But then again, as Mr. Violini said, these steps were “unique.”
Roman Catholic tradition holds that these are the marble stairs that Jesus climbed at his judgment before the Roman prefect Pontius Pilate. The stairs are said to have been brought to Rome in A.D. 326 from Jerusalem by St. Helena, the mother of Emperor Constantine and collector of all things Jesus. (She also thought she found various remnants of his crucifixion, including nails and wood from the “true cross.”)
It quickly became an attraction for pilgrims, who still make their way up the staircase — housed in a sanctuary across from the Basilica of St. John Lateran — on their knees, as an act of penance as they meditate on the passion of Christ.
But not on the marble itself, which was covered for protection by a walnut wood encasement in 1723. Now, for the first time in 300 years, it is to be revealed to the public by Mr. Violini and church officials on Thursday. The stairs will remain uncovered for two months while the wood casing is being restored.
Over the centuries, pilgrims’ hands, feet and knees have left furrows in the marble, which is worn through in some places to the rough stone underneath.
“We didn’t have any idea what would be there, and every step we uncovered brought a new emotion,” Mr. Violini said. The overall effect is of a cascade of water, frozen in time.
The grooves split at a grate — marked by a medieval cross — that covers a spot believed to be stained by a drop of Jesus’ blood. The marble has been worn away by countless pilgrims poking their fingers through the grate.
By touching that spot, worshipers were trying to connect with the sacred, said the Rev. Francesco Guerra, the rector of the sanctuary, which was entrusted to the care of the Passionist fathers in the 19th century.
Father Guerra said that restorers had found coins, photographs, prayers and handwritten requests for blessings amid centuries’ worth of dust.
The reveal of the staircase is the coda of a 20-year project to restore the 16th-century sanctuary, which was designed to house the steps by the architect Domenico Fontana, who transformed Rome under Pope Sixtus V.
Although the stairs and chapel are a major pilgrimage site, drawing about half a million visitors a year, finding donors for the restoration was not easy.
“Not everyone gets the Holy Stairs. It’s not a glamorous restoration like the Sistine Chapel,” said Mary Angela Schroth, who is overseeing the restoration. She described it as “the last great conservation project of late 16th century Rome.”
Working from 1587 to 1590, a team of artists including the Flemish landscapist Paul Bril frescoed scenes from the Old and New Testaments over nearly a mile of the sanctuary’s walls. Over the centuries, candle smoke, pollution and overpainting had rendered the frescoes nearly illegible. “The paintings had become so dark you couldn’t recognize the scenes,” Father Guerra said.
Eventually, Ms. Schroth managed to capture the attention, and the wallets, of the Getty Foundation and the Patrons of the Arts in the Vatican Museums, a group of mostly British and American philanthropists, as well as individual donors like John and Virginia Gildea of Palm Beach, Fla., who restored a chapel in the sanctuary as well as a fresco cycle of the Stations of the Cross.
The restoration of the stairs was supposed to last four years, but it took six, and an initial budget of 2 million euros, or about $2.25 million, went over budget by about 600,000 euros. The Vatican restorers were meticulous, even touching up centuries of graffiti on the frescoed walls.
Long-lost details emerged from the restoration of the bright, late Mannerist frescoes (and from the installation of modern LED lighting). “We recovered the luminosity and the spirit of the late 16th century,” said Mr. Violini, whose résumé also includes restorations of Raphael’s Rooms, the Sistine Chapel and the Pauline Chapel at the Vatican.
The restoration could draw more tourists to the sanctuary. The site last made headlines more than 20 years ago, when the restoration of late 13th-century frescoes in the private chapel at the top of the stairs known as the Sancta Sanctorum revived a debate over the origins of Renaissance art.
The frescoes were found to have been by an unidentified artist whose innovative style suggested that Rome possessed a painting school as accomplished as that of Tuscany, long seen as the birthplace of Renaissance art.
The last pope to visit the Sancta Sanctorum was Pius IX, who went there on the eve of the invasion of Piedmontese troops that put an end to temporal papal power in 1870.
The chapel holds venerated relics from saints and martyrs from the first centuries of Christianity, as well as the Acheiropoieta, a jewel-encrusted image of Jesus thought to have come into existence miraculously.
Once fully restored, the walnut planks — which are in remarkably good shape — will be placed back on the steps. “Wood is more elastic than marble, so it is more resistant” to wear, Mr. Violini said
For now, though, pilgrims and tourists will be able to kneel in the exact path that millions took before them.
“This need to touch is a concrete way of seeking the benediction of God,” Father Guerra said.