Adi Shankaracharya Did Not Establish Shankar Mutts

Then Shankaracharya dates back to between 4300-4000 BC! But the Bhakti Literature mentions Gnana Sambhanda around 7 Century AD when Tirunavukkasar is mentioned as a contemporary of Sambanda. This is supported by to other evidence in Tamil. So Shankaracharya' date may be after 7 Century AD. Now to the view that Shankaracharya did not establish the four Mutts.