Scholars know the Nabataeans were in Petra since at least 312 B.C., says archaeologist Zeidoun Al-Muheisen of Jordan's Yarmouk University.
Al-Muheisen, who has been excavating in Petra since 1979 and specializes in the Nabataean period, says no one has yet found any archaeological evidence dating back to the fourth century B.C. The earliest findings thus far date back only to the second and first centuries B.C.
But more clues remain beneath the surface. "We have uncovered just 15 percent of the city," he says. "The vast majority—85 percent—is still underground and untouched."
Numerous scrolls in Greek and dating to the Byzantine period were discovered in an excavated church near the Winged Lion Temple in Petra in December 1993.
Researchers at the American Center of Oriental Research in Amman, the capital, are now analyzing the scrolls and hope they will shed light on life in Petra during this period.
Once Rome formally took possession of Petra in A.D. 106, its importance in international trade began to wane. The decay of the city continued, aided by earthquakes and the rise in importance of sea trade routes, and Petra reached its nadir near the close of the Byzantine Empire's rule, around A.D. 700.
Visitors today can see varying blends of Nabataean and Greco-Roman architectural styles in the city's tombs, many of which were looted by thieves and their treasures thus lost.
Today, local Bedouins selling tourist souvenirs hawk their wares not far from the place where Arabs believe Moses struck a rock with his staff, causing water to burst forth.