History of the Romans in Arabia

[1] Mostly in order to secure the maritime route from piracy, the Romans organized an expedition under Aelius Gallus in which the port of Aden (then called Eudaemon) in southern Arabia was occupied temporarily.

[2] Frankincense and myrrh, two spices highly prized in antiquity as fragrances, could only be obtained from trees growing in southern Arabia, Ethiopia, and Somalia.

The Incense Route ran along the western edge of Arabia's central desert about 100 miles inland from the Red Sea coast.

Augustus commanded Gallus to undertake a military expedition to Arabia Felix in 26 BC, where he was to either conclude treaties making the Arabian people foederati (i.e., client states), or to subdue them if they resisted.

According to Theodor Mommsen, Aelius Gallus sailed with 10,000 legionaries from Egypt and landed at Leuce Kome, a trading port of the Nabateans in the northwestern Arabian coast.

When the emperor Trajan started his military expansions toward the east Rabbel II Soter, one of Rome's client kings, died.

In 356, the city of Hegra is again mentioned, as being led by a mayor of local origin, but it seems to have been very little [...][12]The conquest of Arabia was not officially exulted until the completion of the Via Traiana Nova in 120s.

It was not until the project was finished that coins, featuring Trajan's bust on the obverse and a camel on the reverse, appeared commemorating the acquisition of Arabia.

[13] Particularly interested in the East, Trajan secured Indian Ocean trade by establishing a garrison on tropical Farasan island, in the south of that sea.

[14] Hadrian probably restructured the province after the Trajan expansion, reducing the area to nearly half the original size (at the west of what was called the Limes Arabicus) in order to better defend Arabia Petraea from raiders and enemies.

Under emperor Septimius Severus Arabia Petraea was expanded to include the Leja' and Jabal al-Druze, rough terrain south of Damascus, and also the birthplace of M. Julius Phillipus (Philip the Arab).

Geographically, the Ghassanid kingdom occupied much of Syria, Mount Hermon (Lebanon), Jordan and Palestine, and its authority extended via tribal alliances with other "Azdi" tribes all the way to the northern Hejaz as far south as Yathrib (Medina).

That it would matter to an issue in Gaul that a single legion in a backwater province on the other side of the empire would rebel indicates the political sway that Arabia had amassed.

The province was conquered by the Arab Muslims under the Caliph Umar in the early 7th century: the Legio III Cyrenaica was destroyed defending Bostra in 630, ending the Roman presence in Arabia.