At the crossroad of commerce, the Nabatean kingdom flourished, holding a monopoly for the trade of incense, myrrh and spices. Situated on the overland caravan route and connected to the Red Sea port of Egra Kome, Mada'in Saleh, then referred to as Hegra among the Nabateans, reached its peak as the major staging post on the main north–south trade route.
Post-Nabatean and Roman
In 106 CE, the Nabatean kingdom was annexed by the contemporary Roman Empire. The Hedjaz region, which encompasses Hegra, became part of the Roman province of Arabia.
The Hedjaz region was integrated into the Roman province of Arabia in 106 CE. A monumental Roman epigraph of 175-177 CE was recently discovered at Al-Hijr (then called "Hegra" and now Mada'in Saleh).
The trading itinerary shifted from the overland north–south axis on the Arabian Peninsula to the maritime route through the Red Sea. Thus, Hegra as a centre of trade began to decline, leading to its abandonment. Supported by the lack of later developments based on archaeological studies, experts have hypothesized that the site had lost all of its urban functions beginning in the late Antiquity (mainly due to the process of desertification).
Recently has been discovered evidence that Roman legions of Trajan occupied Madain Salih in the Hijaz mountain area of north-eastern Arabia, increasing the extension of the "Arabia Petraea" province of the Romans in Arabia.
The history of Hegra from the decline of the Roman Empire until the emergence of Islam remains unknown. It was only sporadically mentioned by travellers and pilgrims making their way to Mecca in the succeeding centuries. Hegra served as a station along the religious route, providing supplies and water for pilgrims. Among the accounts is a description made by 14th-century traveller Ibn Battuta, noting the red stone-cut tombs of Hegra, by then known as Al-Hijr. However, he made no mention
