The nomadic tribes from Arabia Deserta frequently invaded the surrounding countries -i.e., Arabia Felix and Mesopotamia-, where they sometimes managed to settle. Hardly anything about these isolated "people without history" is known. In the Parthian and Roman period, several Arabian towns were founded in what is now Syria and Iraq: Palmyra, Emesa, Edessa, Hatra, Characene and Gerrha.
These Arabs lived between Egypt and Mesopotamia, and could not maintain their isolated way of life. They build several towns; Petra became their famous capital.
The oldest reference to these Arabs can be found in the biblical book Genesis, where Arabian merchants buy and sell Jacob's son Joseph. Other references can be found in the Assyrian king Salmanasser's account of a battle in 853 BC and in the reports about a kingdom named Aribi, that is mentioned from Tiglath-Pileser III (ruled 745-727) onward and was an Assyrian vazal until the second half of the seventh century. Later, the Arabs were subdued by the Babylonian king Nabonidus, who made the oasis of Temâ his capital and reached Iatribu.
According to the Greek researcher Herodotus, the Persian king Cambyses did not subdue the Arabs when he attacked Egypt in 525 BC. His successor Darius I does not mention the Arabs in the Behistun inscription from the first years of his reign, but mentions them in later texts; this suggests that Darius conquered this part of Arabia. There are no indications that these Arabs were no loyal subjects of later Persian kings.
After the Macedonian king Alexander the Great had conquered the Persian empire (between 335 and 323), this part of Arabia remained more or less autonomous for centuries. In 106 AD, however, it was made a province of the Roman empire by the emperor Trajan.
In Antiquity, modern Yemen and Oman were famous for their incense and cinamon - the latter being imported from India. When Alexander the Great had conquered the Persian empire, he wanted to launch a naval expedition to Arabia Felix, but he died several days before the expedition started.
Although this expedition had come to nothing, southern Arabia was now part of a larger world, and several towns are known to date from this period. In the Mediterrean world, the reputation of these rich countries was well known from the incense traders; the Roman emperor Augustus sent a legion to conquer Yemen, but it was unable to keep the country occupied.
Several new towns were founded along the incense road; the most important was Iatribbu. Mecca was a little off the main road.