The revenue system of the Delhi Sultanate produced a considerable proportion of the Indian slave population as these rulers, and their subordinate shiqadars, ordered their armies to abduct large numbers of locals as a means of extracting revenue. While those communities that were loyal to the Sultan and regularly paid their taxes were often excused from this practice, taxes were commonly extracted from other, less loyal groups in the form of slaves. Thus, according to Barani, the Shamsi "slave-king" Balban (r. 1266–87) ordered his shiqadars in Awadh to enslave those peoples resistant to his authority, implying those who refused to supply him with tax revenue. Sultan Alauddin Khalji (r. 1296–1316) is similarly reported to have legalised the enslavement of those who defaulted on their revenue payments. This policy continued during the Mughal era.