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 center 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 evidence has been discovered that the Roman legions of Trajan occupied Mada'in Salih in northeastern Arabia, increasing the extension of the Arabia Petraea province of the Romans in Arabia.