The senior branch of the dynasty, founded by Waththab ibn Sabiq in 990, ruled the Euphrates cities of Harran, Saruj and Raqqa more or less continuously until the late 11th century.

Numayrid emirs continued to hold isolated fortresses in Upper Mesopotamia, such as Qal'at an-Najm and Sinn Ibn Utayr near Samosata until the early 12th century, but nothing is heard of them after 1120.

The Numayrids ruled the Diyar Mudar region in the western Jazira (Upper Mesopotamia), controlling the lands between Harran, Saruj and Raqqa more or less continuously between 990 and 1081.

[5] Unlike most of the children of Amir ibn Sa'sa who became progenitors of large branches of the tribe, Numayr had a different maternal lineage and did not enter into any tribal alliances.

The 13th-century chronicler Ibn al-Adim holds that the Banu Numayr migrated to Upper Mesopotamia from al-Yamama in 921,[6] while the historian Clifford Edmund Bosworth places their arrival at sometime between 940 and 955.

[9] These Bedouin groups largely uprooted the pre-established, sedentary Arab tribesmen of Upper Mesopotamia, rendered the roads unsafe for travel and severely damaged crop cultivation.

[3] Six years later, they were employed in the same fashion by Sayf ad-Dawla (r. 945–967), the Hamdanid emir of Aleppo,[4][11] against incursions by the Ikhshidid leader Abu al-Misk Kafur.

[11] This hampered the Hamdanids' ability to effectively control the southeastern areas of Diyar Mudar, near the hostile Byzantine frontier, necessitating further reliance on the Banu Numayr.

[11] To that end, Sayf's successor, Sa'd ad-Dawla, assigned members of the tribe to governorships in cities such as Harran,[11] to which he appointed an emir of the Banu Numayr, Wathhab ibn Sabiq.

[3] Later in 990, Waththab took over the fortified town of Saruj to the west of Harran,[12][13] and in 1007, he conquered Raqqa from its Hamdanid governor, Mansur ibn Lu'lu'.

[14] Furthermore, during Shabib's early reign, Edessa's inhabitants grew increasingly antagonistic toward Utayr, likely because he killed the city's popular deputy ruler.

[11][13] In 1030, Nasr ad-Dawla, the Marwanid emir of Mayyafariqin, intervened on behalf of Edessa's inhabitants, killed Utayr and captured the city.

[12] Accounts vary as to whether Nasr ad-Dawla or the Mirdasid emir of Aleppo, Salih ibn Mirdas, arbitrated the division of Edessa following Utayr's fall.

[13][15] Because he was unable to effectively challenge the Byzantines, Shabib focused on expanding his domain eastward and northward into Marwanid and Uqaylid territory.

[18] Shabib's sister, al-Sayyida Alawiyya, who was noted for her intelligence and beauty, was married to Nasr ibn Salih and later played an important role in Aleppan politics.

[21] At the time of Shabib's death, al-Sayyida lived in al-Rafiqah, immediately adjacent to Raqqa, having moved there with Thimal after the Fatimid occupation of Aleppo.

[21] She sought to seize Raqqa from her brothers' deputy governor, and married Thimal "to uphold her authority and safeguard her interests", according to Ibn al-Adim.

[21] Around the same time, al-Dizbari, wary of Thimal's growing power base in Upper Mesopotamia, purchased the Qal'at Ja'bar fortress, north of Raqqa, from Shabib's son Mani'.

[24] He switched the Numayrids' formal allegiance from the Fatimids to the Seljuq sultan Tughril Beg of Baghdad, who sent Mani' robes of honor and issued a decree granting him Raqqa.

[25] The Fatimids attempted to stabilize the situation in Upper Mesopotamia and assist the anti-Seljuq general Arslan al-Basasiri, whom they sought to use to invade Iraq.

[30] That year, Mani' extended Numayrid territory to its southernmost extent by capturing the Khabur/Euphrates-area fortress towns of al-Rahba and al-Qarqisiyah (Circesium).

[31] In 1060, after al-Basisiri's forty-week reign came to an end with his defeat and execution by the Seljuqs, Mani' married one of his daughters to Uddat ad-Din to establish ties with the caliph's family.

[31] According to historian D. S. Rice, the Numayrids greatly benefited from the "Basasiri incident", having gained Raqqa from the Mirdasids and given large sums by the Fatimids "without committing themselves" to the "hazardous enterprise" of participating in al-Basasiri's coup attempt.

[18] In 1081, the Uqaylid emir Muslim ibn Quraysh, backed by the Seljuqs, conquered Harran from Mani's successor(s),[34] whose names were not recorded in the sources.

[18] Despite the loss of their capital and much of their power, the Numayrids maintained a presence in the region into the 12th century, holding onto a few fortresses that were isolated from each other, including Qal'at an-Najm on the northern Euphrates and Sinn Ibn Utayr.

[36][38] In 1110, the Numayrids, led by a certain Jawshan an-Numayri, seized Raqqa from its Turkmen governor Ali ibn Salim, who they killed,[36][39] but were dislodged a short time later.

Once in power, the Numayrids resolved to protect, govern and tax the communities inhabiting the agricultural territories and towns they controlled, rather than plunder them.

[8][10] As such, Numayrid emirs and chieftains refrained from residing within the cities they controlled; instead, they formed mini-principalities in the countryside surrounding their respective strongholds.

[42] Excavations of Harran's modern citadel revealed that Mani's construction partly consisted of two small, square basalt towers connected to each other by a decorated arch.

[43] Rice states that the inscription represents the "oldest Islamic text so far found at Harran and the only surviving epigraphic document of the Numairid dynasty".