The story of this great change in the conception of the history of Earth is not a simple one.The chronicle of this great change can be broken into five periods; ran from AD 1600-1700.The second is that the rates of the physical processes in question are variable and knowledge of them was incomplete.
In the pre-scientific world view the issue of the age of the Earth was a theological question.
He would have answered that the Earth was ancient, that there had not been a Noachian flood, and that the species of life had not been fixed over the history of Earth.
In short, Genesis was an allegory and not literal history.
There were various attempts to estimate the Earth's age, working back from sedimentation rates and other geophysical phenomena.
The attempts produced estimates from about 100 million years up to several billion years. The first is that the geological history was still being reconstructed.