Awdaghust enters the written record around 889, when the Arab geographer al-Yaqubi placed it fifty stages south of Sijilmasa across the open desert, ruled by a king who, in his telling, raided the lands to the south. By the tenth century it was a power in its own right. Ibn Hawqal, writing around 977, reported that its king kept relations with the ruler of distant Ghana, ten days' caravan journey to the east. The trade was a chain of mutual need: Ghana grew rich on gold, but Ghana's kings, Ibn Hawqal noted, stood in pressing need of the salt that came down through Awdaghust from the lands of Islam. Gold flowing north, salt flowing south, and this oasis sitting astride the exchange.

The fullest portrait comes from al-Bakri, the Andalusian scholar who finished his Book of Routes and Realms in 1068 without ever leaving Spain, drawing on earlier eyewitnesses. He described a large, crowded town built on sand beneath a barren mountain, with one congregational mosque and many smaller ones. Around it lay gardens of date palms. Farmers grew wheat by hoeing the ground and hauling water up in buckets. Excellent cucumbers ripened there, with a few fig trees and vines and broad plantations of henna. Cattle and sheep were beyond counting, and honey arrived from the south. The merchants, many of them from Ifriqiya in what is now Tunisia, enjoyed what al-Bakri flatly called huge wealth.

That wealth had a darker foundation. Al-Bakri recorded, without comment, that a single inhabitant of Awdaghust might own a thousand enslaved people or more. The trans-Saharan trade that carried gold and salt carried human beings too, marched north across the desert in numbers that made some merchants spectacularly rich. The polished description of cucumbers and henna and full markets sits alongside that fact, and it should. The men who paid for everything in gold did so partly because other people had no choice in the matter. The prosperity al-Bakri admired was built on a scale of bondage that the comfortable diners of the city seem rarely to have questioned.

In 1054 a Berber religious movement reached the city. Al-Bakri names the leader, Abd Allah ibn Yasin, and describes a flourishing town of markets and palm groves taken by force. His account is unsparing: the Almoravids violated its women and declared everything they seized to be the community's lawful plunder. Their stated reason was political. Awdaghust had recognized the authority of the ruler of Ghana, and for that its people were punished. The town never fully recovered. By 1154 al-Idrisi described only a small, thirsty place where the inhabitants scraped a living from their camels. The terminus of the great caravan route shifted east to Oualata, and Awdaghust faded from the maps.

French archaeologists dug at Tegdaoust between 1960 and 1976 and read the city's life in its layers. The earliest occupation reaches back to the seventh to ninth centuries; the first mud-brick buildings rose in the late ninth or early tenth; stone construction followed in the eleventh, the city's peak. The site is an artificial mound twelve hectares across, partly abandoned by the close of the twelfth century and emptied entirely by the fifteenth, with only a faint resettlement long after. The science-fiction writer Bruce Sterling once set a story here, a lavish dinner at which a fortune-teller foretells the city's ruin and is laughed out of the room. The diners are wrong about the seer. They are right about Awdaghust.