 Indian merchants, scholars, and sometimes armies were involved in this transmission; South-East Asians took the initiative as well, with many sojourning in Indian seminaries and translating Buddhist and Hindu texts into their languages.After the 10th century, Muslim Central Asian nomadic clans, using swift-horse cavalry and raising vast armies united by ethnicity and religion, repeatedly overran South Asia's north-western plains, leading eventually to the establishment of the Islamic Delhi Sultanate in 1206.The sultanate was to control much of North India and to make many forays into South India.