Ive been reading a book lately called The Atlantis Enigma by Herbie Brennan its really fascinating.
I was reading a chapter on a discovery by archaeologist Henry Layard which was a crystal artefact.
"At first, archaeologists concluded the disc must be an ornament of some sort, but then David Brewster became interested in the find. Brewster was an
eminent Scottish physicist noted for his experimental work in optics and polarised light. Today he is best remembered as the inventor of the
Kaleidoscope and the man who first produced three-dimensional images using a modified stereoscope. Brewster examined the artefact and announced, in
1853, that it was a well-made optical lens. This find is not unique. Some seventy-five similar lenses of varying dates have subsequently been found at
sites that range from central Turkey through Crete to Troy. Current orthodoxy has it they were all decorative furniture inlays". ( The Atlantis
Enigma by Hernie Brennan)
Here is two pages that i have found that sort of explain why there must have been telescopes around at that time.
Worlds Oldest Telescope?
Lenses??? 
