Home of the prestigious Koranic Sankore University and other madrasas, Timbuktu was an intellectual and spiritual capital and a center for the propagation of Islam throughout Africa in the 15th and 16th centuries.
Timbuktu was a center of Islamic scholarship under several African empires, home to a 25,000-student university and other madrasahs that served as wellsprings for the spread of Islam throughout Africa from the 13th to 16th centuries. Sacred Muslim texts, inbound editions, were carried great distances to Timbuktu for the use of eminent scholars from Cairo, Baghdad, Persia, and elsewhere who were in residence in the city. The great teachings of Islam, from astronomy and mathematics to medicine and law, were collected and produced here in several hundred thousand manuscripts. Many of them remain, though in a precarious condition, to form a priceless written record of African history.
Now a shadow of its former glory, Timbuktu strikes most travelers as humble and perhaps a bit run down. But the city’s former status as an Islamic oasis is echoed in its three great mud-and-timber mosques: Djingareyber, Sankore, and Sidi Yahia, which recall Timbuktu's golden age. These 14th and 15th-century places of worship were also the homes of Islamic scholars known as the Ambassadors of Peace.
Religion wasn’t the city’s only industry. Timbuktu sits near the Niger River, where North African’s savannas disappear into the sands of the Sahara, and part of its romantic image is that of a camel caravan trade route. This characterization had roots in reality and in fact, continues to the present in the much-reduced form. Salt from the desert had great value and, along with other caravan goods, enriched the city in its heyday. It was these profitable caravans, in fact, that first brought scholars to congregate at the site.
According to nationalgeographic.com