Nasir al-Din al-Tusi
Islam does not recognize any castes, but, when it came to Persia and India, the existing divisions in these regions were adopted among the local Muslim societies. 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).