India was traditionally subjected to invasions from its western borders for centuries. There were Kushanas, Shakas, Barbaras, Hunas, Kambojas, Yavanas, Parasikas, Tusharas then khiljis, mongols, mughals, afgans etc. all came through the western and north western borders of India. Why there were no such invasions from our eastern sector, either through land or sea? Was it that there were no strong kingdoms or armies in east Asia who were interested in plunder and looting? Or was it that eastern Indian Kingdoms were traditionally too strong for them to even think of such an attack? How significant was Himalayas to stop Chinese to India when they had invaded Tibet in 1st millenia?
