Muslim communities in South Asia apply a system of social stratification. It developed as a result of ethnic segregation between the foreign conquerors (Ashraf) and the local converts (Ajlaf), as well as influence of the indigenous Hindu culture. Islam does not recognize any castes.
Islam does not recognize any castes, however, by the time it came to Persia and India, the existing divisions in these regions were adopted among the local Muslim societies. The ancient Persian society had a social stratification system analogous to the Indian varna system. The Sasanian society retained this system with some changes, even after the Muslim conquest of Persia in the 7th century. Evidence of social stratification can be found in several later Persian works, such as Siyasatnama of Nizam al-Mulk (11th century), Akhlaq-i Nasiri of Nasir al-Din al-Tusi (13th century), and Jam-i-Mufidi (17th century).
The Muslims who came to the subcontinent during the 12th century Muslim conquest of India were already divided into social classes such as priests, nobles and others. Further, a racial segregation demarcated the local Muslim converts from those of foreign origin. The foreigners claimed a superior status as they were associated with the conquerors, and categorized themselves as Ashraf ("noble"). Over time, the Indian Muslim society also split on the basis of the existing Hindu caste system. According to M. N. Srinivas (1986), Indian Hindu converts to Islam brought their original caste system to the Muslim society in the region. On the other hand, Louis Dumont (1957) believes that the Islamic conquerors consciously adopted the Hindu caste system.