 According to social anthropologist Dipankar Gupta, guilds developed during the Mauryan period and crystallised into "jatis" in post-Mauryan times with the emergence of feudalism in India, which finally crystallised during the 7–12th centuries.However, other scholars dispute when and how "jatis" developed in Indian history.Barbara Metcalf and Thomas Metcalf, both professors of History, write, "One of the surprising arguments of fresh scholarship, based on inscriptional and other contemporaneous evidence, is that until relatively recent centuries, social organisation in much of the subcontinent was little touched by the four "varnas".