Wadi Sirhan historically served as an important trade route between Arabia and
Syria. The
Assyrian king
Esarhaddon launched a campaign against the Bazu and Khazu tribes in Wadi Sirhan in the 7th century BCE.
Roman and Byzantine eras The basin continued to serve as an important route during the Roman era, connecting the
Arabia Petraea province with the Arabian Peninsula. Though its strategic value emanated from its role as a gateway for trans-Arabian trade and transportation, Wadi Sirhan was also a significant source of salt. At its northern end, it was guarded by the
fortress of Azraq, while its southern end was guarded by the fortress of
Dumat al-Jandal. At both forts inscriptions were found indicating the presence of troops from the
Bosra-based
Legio III Cyrenaica. Wadi Sirhan was the region from which the
Salihids entered Syria and became the principal Arab
federates of the
Byzantine Empire throughout the 5th century CE. When the Salihids were succeeded by the
Ghassanids at the beginning of the 6th century, Wadi Sirhan came to be dominated by the latter's allies, the
Banu Kalb. The Ghassanids were charged by the Byzantines with supervision over the region after Emperor
Justinian I dismantled the
Limes Arabicus, a series of garrisoned fortifications guarding the empire's eastern desert frontiers, . The Ghassanids and the Kalb essentially supplanted the
limes. The Ghassanid
phylarch Arethas passed through the depression on his way to defeating the
Banu Tamim. Likewise,
Alqama, a poet of the latter tribe, passed through Wadi Sirhan to meet with Arethas to lobby for his brother's release from captivity.
Early Islamic era Following the Muslim conquest in 634 CE, the basin became an often fought over frontier between the Banu Kalb and their distant kinsmen from the
Banu al-Qayn.
Modern era The lowland gained its current name following the migration of the
Sirhan tribe, purported descendants of the Banu Kalb, to the Dumat al-Jandal region from the
Hauran . Before their migration, Wadi Sirhan was known as Wadi al-Azraq after the
Azraq oasis. During the
Arab Revolt,
T. E. Lawrence said of the Wadi, "We found the Sirhan not a valley, but a long fault draining the country on each side of it and collecting the waters into the successive depressions of its bed." By the late 19th century, the
Ruwalla, which is a Saudi tribe, were the predominant
Bedouin tribe of Wadi Sirhan.
Nuri Shalan, the emir of the tribe from 1904 to 1942, was a signatory of the
Hadda Agreement between the
Emirate of Transjordan and the
Sultanate of Nejd, the precursors of modern-day Jordan and Saudi Arabia, respectively. The treaty resulted in most of Wadi Sirhan becoming part of Saudi Arabia, while Jordan retained the basin's northwestern corner around Azraq. ==See also==