After Sunni Ali Ber died, Sunni Baru, his son and intended successor, was challenged by Muhammad because he was not seen as a faithful Muslim. This gave one of Sunni Ali Ber's generals, Muhammad Ture, a reason to challenge his succession. General Ture defeated Baru and ascended to the throne in 1493.
General Ture, later known as Askia Muhammad I or Askia the Great, subsequently orchestrated a program of expansion and consolidation which extended the empire from Taghaza in the North to the borders of Yatenga in the South; and from Air in the Northeast to Futa Djallon in Guinea. Instead of organizing the empire along Islamic lines, he tempered and improved on the traditional model by instituting a system of bureaucratic government unparalleled in Western Africa. In addition, Askia established standardized trade measures and regulations, initiated the policing of trade routes and also established an organized tax system. He was overthrown by his son, Askia Musa, in 1528.
Askia encouraged learning and literacy, ensuring that Songhai's universities produced the most distinguished scholars, many of whom published significant books and one of which was his nephew and friend Mahmud Kati. To secure the legitimacy of his usurpation of the Sonni dynasty, Askia Muhammad allied himself with the scholars of Timbuktu, ushering in a golden age in the city for scientific and Muslim scholarship. The eminent scholar Ahmed Baba, for example, produced books on Islamic law which are still in use today. Muhammad Kati published Tarikh al-fattash and Abdul-Rahman as-Sadi published Tarikh al-Sudan (Chronicle of Africa), two history books which are indispensable to present-day scholars reconstructing African history in the Middle Ages.