James Skinner's treatise on India's caste system was based on Sanskrit sources that were later translated into Persian.
Notes on verification
Confirmed by multiple independent sources including a scholarly database (Perso-Indica), a museum/academic exhibition site, and a historian's article, all consistently describing the Tashrih al-Aqvam as based on Sanskrit sources (Vedas and Shastras) translated into Persian for Skinner.
Sources
- The Library of Congress Has Digitized 155 Persian Texts Dating ... (smithsonianmag.com)
- http://perso-indica.net/work/treatises_of_mixed_contents/tasrih_al-aqwam (perso-indica.net)
- https://sites.asiasociety.org/princesandpainters/tashrih-al-aqvam-album/ (sites.asiasociety.org)
- https://ranasafvi.com/james-skinner-and-tashrih-al-aqvam/ (ranasafvi.com)