When an Israeli court ruled last month that Jews could pray on the Temple Mount in Jerusalem—if it was done quietly—the surprise decision seemed sure to spark yet another round of unrest in a city that in May endured some of its worst violence in years. Palestinians and the governments of Turkey and Egypt immediately condemned a decision that devout Jews hailed as a victory for religious freedom. A judge then quickly reimposed the longstanding prayer ban, narrowly averting an international crisis.

The trouble began on Yom Kippur, when a Jewish man engaged in prayer on the city’s 37-acre ancient acropolis that Muslims call the Noble Sanctuary, or Haram al-Sharif. Israeli police, who are in charge of security at Islam’s third holiest site, ordered him to stop. Preventing Jewish prayer at a place Judaism also holds sacred might seem a peculiar job for Israeli police, and their decision to eject the man might appear a blatant restriction of a basic human right. But to understand this prohibition, and why this religious complex is at the heart of the Israeli-Palestinian conflict, you have to dig deeper—literally.

Few realize that the roots of strife here lie not with Jews or Muslims, but in the actions of zealous European and American Christians eager to unearth the biblical past. Starting in the mid-19th century, Western explorers descended on Jerusalem, then part of the Ottoman Empire, to probe beneath the largely medieval city to find the tomb of David, the treasures of Solomon, and the true site of Jesus’s crucifixion.

This era began when a French senator in 1863 dug up a sarcophagus with bones that he claimed were those of an ancient Judean queen. The move enraged the Jewish community. “Even the Muslims are upset because of this wickedness,” a Hebrew-language newspaper reported. With the permission of the Ottoman governor, the stone casket and human remains were nevertheless shipped to the Louvre.

Not willing to be bested by Catholic France, British Protestants in 1864 launched their own campaign to retrieve biblical artifacts. A British army officer named Charles Warren even resorted to gunpowder to blast his way through the caves and cellars that honeycomb Jerusalem’s subterranean world. Since many of his activities took place adjacent to the Noble Sanctuary, some suspected the British had a secret plan to bring down the walls supporting the 1400-year-old Dome of the Rock and al-Aqsa Mosque.

For the next half century, as the Ottoman Empire began to fray, European explorers competed to find remnants of the biblical period below, while their nations competed to control the city above. Their ultimate Holy Grail, however, remained strictly off limits. Christian excavators yearned to dig beneath the acropolis for remnants of the last Jewish temple, destroyed by the Romans in 70 C.E. (common era). Even Kaiser Wilhelm II was rebuffed when he made a personal plea to the Muslim mufti during an 1898 visit.