Huh? My head is spinning. My history tells me a 2600 Buddhist monastery is not possible, since the Buddha was around 2500 years ago — and any monastery dedicated to his disciplines would have waited some time after that, especially as far away as Afghanistan.
Just sayin’.
I think you have to give some mild allowances for dating since even the best methods may have a give or take of a century or two. Since we seem to have fairly good oral and written traditions of when Buddha was born, then a dating of the artifacts as 2600 years not be so far fetched.
The date of Buddha’s birth is an estimate that’s pretty broad — 563 BC to as long ago as 623 BC. And 563 BC is nearly 2600 years ago. :’)
There was a lot of travel from India up to the Silk Road and this route was the primary route for travel between China and India. Buddhism came very early to Afghanistan.