[John Preston]

My friends,
Help solve the next puzzle.
Me into the hands of work, " Adoration of the Shepherds ," which attributiruyu as " nazareyskaya school."
Perhaps a copy of the picture Joan Friedrich Overbeck (Johann Friedrich Overbeck)?
But if it is a copy , then where is the original and who is the author?
On Ebee now sold similar picture, but there is a difference ...

I would be very grateful for the information !