JERUSALEM -- In the hours before dawn, a Muslim custodian carrying an ancient iron key approaches the heavy wooden doors of the Church of the Holy Sepulcher, the holiest shrine in Christendom.
In a ritual repeated every day for centuries, a voice calls from inside, a ladder is passed through a trap door, and the custodian climbs it to reach the keyhole high in the arched door to unlock it from the outside.
Three monks, one a Catholic Franciscan, the others Greek and Armenian Orthodox, look on as the custodian pulls the door open. The ritual is reversed, with the same three watchful players, when the church closes each night.
For one of the Christian sects to miss a day at this exercise is unthinkable. They would risk losing one of their rights in the sepulcher where rivalries have led to violence.
At this site of the death and resurrection of Jesus, which Pope John Paul II will visit today, this last day of his Holy Land pilgrimage, the religious diversity of Christians is displayed in sublime piety and petty conflict.
There is no corner of this church within the walls of the Old City that is not claimed by one of six sects: the Latins (Roman Catholics), Greeks, Armenians, Ethiopian and Egyptian Copts and Assyrians.
A simple burned-out light bulb in a chapel of disputed custody could cause an ecumenical incident. Trespassing on another's territory while sweeping the dust of pilgrims has resulted in fistfights.
"The important thing is we all recognize this is the site where Jesus was crucified, died and was raised from the dead," said the Rev. Luis Runde, a tall American Franciscan friar with a salt-and-pepper beard. He is assigned to the Holy Sepulcher and goes about his work wearing white-and-blue Nikes with his brown wool habit. "That is the reason we all want a piece of this sacred ground."
By day, the atmosphere in the Holy Sepulcher is anything but contemplative, at times verging on the chaotic. The church is abuzz with the activity of a steady procession of pilgrimage groups, who arrive here after following the Via Dolorosa, the path Jesus walked as he carried his cross to his crucifixion.
Pilgrims jostle each other to touch the marble slab where tradition says Jesus' body was laid, and long lines form to enter the marble-encased Tomb of Christ, for many, the highlight of their Holy Land journey.
"Hurry up, please," a Greek Orthodox priest implores those who linger too long.
But the setting is altogether different in the hours after the opening of the door at 4 a.m.
The plaintive sounds of prayer from various corners echo off the ancient walls. Outside the church entrance, the sound of Christian chant mingles with the prayer call from the Muslim muezzin of the Al Aqsa mosque, next to the Dome of the Rock.
"From 8 p.m. until midnight, the place is idle," Runde says. "At midnight, the Coptic group will start up. Almost all the time there's something going on."
The services can begin to pile up, particularly at the Tomb of Christ, where the Latins, the Greeks and the Armenians all hold services.
One recent morning, Runde had to wait to begin his 4: 30 a.m. Mass while the Armenians concluded their liturgy. Just before the Mass began, the Copts began chanting their liturgy on the other side of the tomb, which provided an accompaniment for the Roman Catholics.
The rules about who controls what and who does what at what time are governed by the Status Quo agreement forged during the 19th century, while Jerusalem and all of Palestine were part of the Turkish Ottoman Empire.
The arrangement for opening and closing the church door goes back even further, to Saladin in 1187. He gave the key to a prominent Muslim family in order to prevent squabbles among the Christian communities.
The descendants of two Muslim families still hold the key: the Judehs, who actually hold the 10-inch key, and the Nusseibehs, who retain responsibility for opening the door. The custodian who comes to perform the task each day is a hired hand.
Despite a history and a present that might appear unedifying, many experience a profound spiritual connection to the source of their faith.
"This is the climax to the whole pilgrimage to the Holy Land," said Gaetano Garibaldi of Tampa, Fla., who attended early morning Mass in the tomb. "To hear Mass in the Holy Sepulcher, where our Lord died and was risen, is truly the pinnacle. Everything else is secondary."
Even the tensions are not necessarily a bad thing, some observers say.
"To me, it's a microcosm of Jerusalem," said Daniel Rossing, a former Israeli minister of religious affairs, who for years mediated disputes at the Holy Sepulcher, including the one over who would change the burned-out light bulb in the disputed chapel.
"There is the ultimate territorial war, because you're not talking about earthly real estate," he said.
"This is one of the best examples of true multiculturalism. There are flare-ups. There are problems.
"But for the most part it's working."