There were hardly any changes in the structure of the Hindu society during the period. According to the Smritis, the Brahmins were at the apex, followed by the Kshatriyas. The duty of the Kshatriyas was to protect the people. The Vaishyas were engaged in trade. It was the duty of the Shudras to serve the other castes, but they were allowed to engage in all occupations. However, severe restrictions were placed on mingling with the outcasts. The Muslims were divided into ethnic and racial groups. There were Turkish, Iranian, Arab, Afghan, and Abyssinian Muslims. During the 13th century, among all the foreigners, the Turkish Muslims were in a dominating position. Besides, the Muslims were divided into many groups on the basis of origin, religion, and occupation. However, the caste divisions did not close social intercourse between the Muslims and the Hindus.