Sachsen of 1752 -- geography & archives

My ancestor, Georg Philip Brehm, born circa 1727, sailed on the ship
''Betty" from Rotterdam to Nova Scotia in 1752. He was accompanied by his
wife, the former Elisabeth Heller and a son. The passenger list stated he
came from Sachsen.

I have had difficulty in finding the exact current area the family came
from. Can anyone tell me what geographic entity now comprizes the area
occupied by the Sachsen of 1752? Also, can anyone supply names, addresses
and emails for archives that may have records for exit permits for this
family?

Many thanks.Jim
JAMES0319@aol.com