Mihirakula which killed 30 m Buddhist in current Punjab and KPK was a hindu Shiva devotee
It led to fall of Gandhara Civilization
Buddhism in India, Pakistan and Afghanistan disappeared due to 100s of reason not just one.
First of all, Buddhism like other religion required
state patronisation. After the Mauryan and Kushan empire, state patronisation of Buddhism disappeared due to lack of Buddhist kingdoms and hence Buddhism stopped flourishing.
Then Buddhism
failed to prove an ideal system for Indians who are full of superstitions, have a rigid caste system and are natural worshippers. The same can be said for
Islam in India. Muslim rulers could not convert the majority of Indians into Islam because of their superstitious mentality and strong belief in caste system. Buddhism thrived in China, Sri Lanka, Myanmar and ASEAN where war and bloodshed was rampant and Buddhism proved to be an ideal system.
Persecution is also another reason. Buddhists were first persecuted by the
Hindu Brahmins. Apart from persecution, Hindus assimilated Buddhists into Hinduism by portraying Lord Buddha as an avatar of Vishnu. Another wave of persecution was initiated by the
Sassanid Zoroastrians in Iran and Afghanistan during the Kushan rule. The final wave of perfect was initiated by
Muslims under
Bakhtiyar Khilji although Buddhism was in a much weaker position when Khilji landed in Bengal.
Migration was another cause. Many Buddhists migrated from India to Tibet, China, Myanmar, Sri Lanka and so on. Some famous Buddhist migrants are
Bodhi Dharma who founded
Shaolin martial arts,
Atisha Dipankara who was the founder of Tibetan Buddhism and many more.
There are other reasons why Buddhism disappeared from India. Will discuss them later.