the Hijaz was the western part of the peninsula, between the Tihama in the southwest and the Najd in the east. It included the Banū Sulaym and the Banū Hilāl. In the north was the territory of Bālī, and in the south that of Huḏayl. After the advent of Islam, the Tihāma was included in the Hijaz, thus the Bedouin tribes in the interior were sometimes included in the Hijaz. It seems that for the grammarians, Hijaz referred to regions defined according to the post-Islamic demarcation. In this way, the urban centers of Mecca, Medina, and Ṯaqīf were included in that region. The term luġa ˀahl