According to some hypotheses, based on the accounts given by medieval Muslim Arab historians, in the third millennium BCE the Semites of the southern Arabian peninsula united under the leadership of Qahṭān.
The Qahṭānites began building simple earth dams and canals in the Marib area in the Sayhad desert.
This area would later become the site of the Dam of Marib.
A trade route began to flourish along the Red Sea coasts of Tihāmah.
An order of high priests appeared in South Semitic culture who are referred to as the "Mukkaribs of the Sabeans" represented by local tribal leaders who came to rule South Arabia and some parts of East Africa.
This period witnessed the reign of the legendary Queen of Sheba mentioned in the Bible, and called Bilqīs by Muslim scholars.
At the end of this period, in the ninth century BCE, an alphabet was introduced, this now meant that South Arabian history could be written down.It is not yet possible to specify with any certainty when the great South Arabian Kingdoms appeared, estimates range (within the framework of the long chronology) from the twelfth until the eighth century BCE.