Islamization of Iran was a long process. As Persian Muslims consolidated their rule, the Muslim population rose from approximately 40% in the mid-9th century to close to 90% by the end of the 11th century. Seyyed Hossein Nasr suggests that the rapid increase in conversion was aided by the Persian nationality of the rulers. Although Persians adopted the religion of their conquerors, over the centuries they worked to protect and revive their distinctive language and culture, a process known as Persianization. Arabs and Turks participated in this attempt.