The most successful local opposition immediately after the fall of Algiers was led by Ahmad ibn Muhammad, of Constantine. He initiated a radical overhaul of the Ottoman administration in his by replacing Turkish officials with local leaders, making Arabic the official language, and attempting to reform finances according to the precepts of Islam. After the French failed in several attempts to gain some of the 's territories through negotiation, an ill-fated invasion force, led by Bertrand Clauzel, had to retreat from Constantine in 1836 in humiliation and defeat. However, the French captured Constantine under Sylvain Charles Valée the following year, on 13 October 1837.