There was no theory of relativity or Quantum mechanics then. I know Gallileo died in 1642. Kepler lived before 1630 and Copernicus before 1543.
If you really want to go back, Euclid lived in the 3rd century BC and there was Vedic Mathematics 1000s of years ago.
Great sage Kapil, the author of Samkhya Philosophy admitted the existence of soul, but denied God, in absence of proof! (Samkhya gave rise to Vedanta and Tantra )
In the Later Vedic age, Philosopher Charvak said, there is no afterlife, so take huge loans, eat butter, enjoy life. There is no God to punish you!
So what? In every age, some people believed in God, some remained sceptics. What I am trying to say is, that Nature's perfect engineering is proof enough of a Higher consciousness. Nature herself is God!
I am not looking for some bearded man on a throne, set upon some clouds, who either sends you to heaven, or, to eternal hellfire, for the work of one tiny lifetime! This idea is indeed preposterous.