Buddhism, which originated in India, gradually dwindled and was replaced by approximately the 12th century. According to Lars Fogelin, this was "not a singular event, with a singular cause; it was a centuries-long process." The decline of Buddhism in the Indian subcontinent coincides with the rise of Islam in that part of the world, especially the Islamic invasions that occurred in the late 12th century. Buddhist and Islamic sources also mention violence against Buddhists by Islamic kings. Unlike multiculturalism and tolerance from Hindu Kings, Islamic policy towards Buddhist Areas was brutal and focused on forced conversions. Another factor was invasions of north India by various groups such as Indo-Iranian Huns, Hephthalite Huns, Alchon Huns, Turco-Mongols, Arabs and Persians and subsequent Islamist destruction of Buddhist institutions such as Taxila and Nalanda and religious persecutions. Religious competition with other Indic religions and later Islam were also important factors. The Persecution by Alchon Huns in 5th century and subsequent destruction of Buddhist centres caused the decline of Buddhism in the northwest Indian subcontinent. A similar process occurred in northeast, where Islamization of Bengal and demolitions of Nalanda, Vikramasila and Odantapuri by Muhammad bin Bakhtiyar Khalji, a general of the Delhi Sultanate are thought to have severely weakened the practice of Buddhism in East India where it previously received strong patronage under the Pala Empire. The total Buddhist population in 2010 in the Indian subcontinent – excluding that of Sri Lanka, Bhutan (both Buddhist majority states) and Nepal – was about 10 million, of which about 7.2% lived in Bangladesh, 92.5% in India and 0.2% in Pakistan. Growth of Buddhism Buddhism expanded in the Indian subcontinent in the centuries after the death of the Buddha, particularly after receiving the endorsement and royal support of the Maurya Empire under Ashoka in the 3rd century BCE. It spread even beyond the Indian subcontinent to Central Asia and China. The Buddha's period saw not only urbanisation, but also the beginnings of centralised states. The successful expansion of Buddhism depended on the growing economy of the time, together with an increase in the number of centralised political organisations capable of change. Buddhism spread across ancient India and state support by various regional regimes continued through the 1st millennium BCE. The consolidation of monastic organisations made Buddhism the centre of religious and intellectual life in India. The succeeding Kanva Dynasty had four Buddhist Kanva Kings. Gupta Dynasty (4th–6th century)