India was ruled by Muslims but 'hinduism' survived, even in those regions under tyrannical Muslim rule. Nalanda and Taxila were both Buddhist centers. Buddhism was highly practised in regions of current day Pakistan (includes Taxila), Afghanistan (perhaps u know about the Bamian Buddhas), Magadh (includes present Bihar, Nalanda, parts of Bengal and UP). And see where the highest numbers of Muslims live now. In India, maximum numbers of Muslims are in Bihar, Bengal, Northern UP. I don't have to say anything more about the state of Afghanistan, Pakistan or Kashmir. And there was no Buddhist who fought against the Muslim invasion. Prithiviraj Chauhan, Laxmi Bai, Maharana Pratap or Shivaaji, all were hindu rulers who fought against Islam. The day when Emperor Ashok converted to Buddhism and started preaching / practising Ahimsa was the day on which the downfall of the Indian empire started.