Najd

Najd is a historical region in the central part of the Arabian Peninsula, covering most of what is now central Saudi Arabia. Its borders are not fixed and have shifted over time due to changing geographical and political definitions, but it is generally bordered by the Hejaz to the west, the Nafud desert in al-Jawf to the north, the ad-Dahna Desert in al-Ahsa to the east, and the Rub' al-Khali to the south. Administratively, it is split into three main provinces: Riyadh Province, which includes Wadi Hanifa, the Tuwaiq escarpment, and the eastern area of Yamama (where the Saudi capital, Riyadh, has been located since 1824), as well as the Sudairi region with its capital at Majmaah; Qassim Province, known for its fertile oases and date palm groves in the highlands along the Wadi Rummah, with its capital at Buraidah, the second-largest city in Najd; and Ḥa'il Province to the north, which features the Jabal Shammar mountains and the Tayy capital of Ḥaʼil. About one-third of Saudi Arabia's current population lives in Najd. It is the ancestral home of the House of Saud, from which it pursued unification with the Hejaz starting in the time of the Emirate of Diriyah.

The name "Najd" comes from the Arabic word for "highland."

In ancient times, the region was home to Al-Magar, an advanced Neolithic culture centered in what is now southwestern Najd. Al-Magar may have been among the first cultures globally to practice widespread agriculture and domesticate animals, especially horses, before desertification set in due to climate change. Radiocarbon dating of objects from Al-Magar suggests they are about 9,000 years old. In November 2017, hunting scenes depicting what appear to be domesticated dogs resembling the Canaan dog and wearing leashes were discovered at Shuwaymis, about 370 kilometers southwest of Ha'il. Dated to 8,000 years ago, these are thought to be the oldest known images of dogs in the world.

In the 5th century AD, northern Arabian tribes threatened the trade route between Yemen and Syria. The Ḥimyarites of Sheba set up a vassal state to control central and northern Arabia, and the Kindites (called Chinedakolpitai in Greek sources) grew strong enough to fill this role. In AD 425, the Ḥimyarite king Ḥasan ibn 'Amr ibn Tubba’ appointed Ḥujr 'Akīl al-Murār ibn 'Amr as the first king of Kindah. The Kingdom of Kinda was established in Najd, but unlike the organized states of Yemen, its kings ruled through personal prestige over allied tribes rather than coercive authority. Their first capital was Qaryat Dhāt Kāhil, now known as Qaryat al-Fāw. The Ghassānids, Lakhmids, and Kindites—all Kahlānī and Qaḥṭānī kingdoms—flourished in Najd. In the 5th and 6th centuries, the Kindites made the first serious attempt to unite central Arabian tribes through alliances, focusing on wars with the Lakhmids. Their most famous king, Al-Ḥārith ibn 'Amr, captured the Lakhmid capital of al-Ḥirah in modern southern Iraq. However, around 529, al-Mundhir recaptured the city and executed King Ḥārith and about fifty of his family members. In 525, the Aksumites invaded Ḥimyar, weakening the Kindites, who lost Ḥimyarite support. Within three years, the Kingdom of Kinda split into four groups—Asad, Taghlib, Qays, and Kinānah—each led by a Kindite prince. These small principalities were overthrown in the 530s and 540s during uprisings by the Adnani tribes of Najd and Hejaz. In 540, the Lakhmids destroyed all Kindite settlements in Najd, forcing most Kindites to move to Yemen, and many Arab tribes switched allegiance to the Lakhmids.

During the 7th century, Muhammad led military expeditions in the area. The first was the Nejd Caravan Raid in 624 against the Quraysh. After learning the route of a Meccan caravan heading to Syria for summer trade, Muhammad ordered Zayd ibn Haritha to intercept it; they successfully raided it and captured 100,000 dirhams worth of booty. The Invasion of Najd occurred in October 625, when Muhammad led his fighters to Najd to deter tribes with suspicious intentions. Some scholars link the expedition of Dhat al-Riqa to this invasion, though the most widely accepted view, according to Saif ar-Rahman al-Mubararakpuri, places it after the fall of Khaybar. This is supported by the presence of Abu Hurayra and Abu Musa al-Ash'ari at the battle—Abu Hurayra converted to Islam only shortly before Khaybar, and Abu Musa al-Ash'ari returned from Abyssinia and joined Muhammad at Khaybar. The prayer of fear rules observed during the Dhat ar-Riqa' campaign were revealed at the Asfan invasion, which scholars say took place after al-Khandaq. The Expedition of Qatan also occurred in Najd, targeting the Banu Asad ibn Khuzaymah tribe, a powerful group connected to the Quraysh living near the hill of Katan in the vicinity of Fayd. Muhammad received intelligence that they planned to raid Medina, so he sent 150 men under Abu Salama 'Abd Allah ibn 'Abd al-Asad to launch a surprise attack.

After Muhammad's death, previously dormant tensions between various groups erupted into the Ridda wars.