Founded in 670, the city of Kairouan flourished under the Ahlabid dynasty in the 9th century. Despite the transfer of the political capital to Tunis in the 12th century, Kairouan remained the first holy city in the Maghreb. Its rich architectural heritage notably includes the Great Mosque, with its columns of marble and porphyry, and the Three-door mosque which dates from the 9th century.