the authority of Shankaracharya

[grif 0]

I have often heard it said especially within the Gaudiya tradition, that Shankaracharya is accredited to bringing back a vast number of indians back to the fold of Hinduism from the deathly sunyavad clutches of Buddhism, which had taken a stronghold in India in order to stop wanton animal sacrifices which Hindus had been performing carelessly due to their misunderstanding of Veda.

 

So is this actually true or is it a type of propaganda for some specific purpose. I have heard that actually the advaita school of thought propogated by Shankaracharya and his guru and param guru was not all that popular in India at the time, but actually more popular in the last one hundred years comparatively.

 

Can anyone fill me in or verify the reality?