Slavery, as with all major ancient and medieval societies, has been a part of Central Asia and South Asia history. The Hindu Kush mountain passes connected the slave markets of Central Asia with slaves seized in South Asia. The seizure and transportation of slaves from the Indian subcontinent became intense in and after the 8th century CE, with evidence suggesting that the slave transport involved "hundreds of thousands" of slaves from India in different periods of Islamic rule era. According to John Coatsworth and others, the slave trading operations during the pre-Akbar Mughal and Delhi Sultanate era "sent thousands of Hindus every year north to Central Asia to pay for horses and other goods". However, the interaction between Central Asia and South Asia through the Hindu Kush was not limited to slavery, it included trading in food, goods, horses and weapons.