Levi states that the forcible enslavement of non-Muslims during Delhi Sultanate was motivated by the desire for war booty and military expansion. This gained momentum under the Khalji and Tughluq dynasties, as being supported by available figures. Zia uddin Barani suggested that Sultan Alauddin Khalji owned 50,000 slave-boys, in addition to 70,000 construction slaves. Sultan Firuz Shah Tughluq is said to have owned 180,000 slaves, roughly 12,000 of whom were skilled artisans. A significant proportion of slaves owned by the Sultans were likely to have been military slaves and not labourers or domestics. However earlier traditions of maintaining a mixed army comprising both Indian soldiers and Turkic slave-soldiers (ghilman, mamluks) from Central Asia, were disrupted by the rise of the Mongol Empire reducing the inflow of mamluks. This intensified demands by the Delhi Sultans on local Indian populations to satisfy their need for both military and domestic slaves. The Khaljis even sold thousands of captured Mongol soldiers within India. China, Turkistan, Persia, and Khurusan were sources of male and female slaves sold to Tughluq India. The Yuan Dynasty Emperor in China sent 100 slaves of both sexes to the Tughluq Sultan, and he replied by also sending the same number of slaves of both sexes.