Question

HISTORY OF SPHERICAL MIRRORS IN ANCIENT CIVILIZATION....

Answer 1

the earlier manufactured mirrors were the pieces of polished stones. parabolic mirrors were described and studied in classical antiquity by the mathematician diodes in his work on burning mirrors. In china people began making mirrors with the use of silver mercury amalgams as early as 500AD. In 16th century, venice, a big city formed for its glass making expertise, became a centre of mirror production using this new technique. 

Answer 2

They were polished stones in earlier times...

Many people may have used lakes or ponds (water) as mirrors too.