But if anyone, well seen in the knowledge, not onely of Sacred and exotick History, but of Astronomical Calculation, and the old Hebrew Kalendar, shall apply himself to these studies, I judge it indeed difficult, but not impossible for such a one to attain, not onely the number of years, but even, of dayes from the Creation of the World.
What did James Ussher do?
In the beginning God created Heaven and Earth … Which beginning of time, according to our Cronologie, fell upon the entrance of the night preceding the twenty third day of Octob. in the year of the Julian Calendar, 710 [or 4004 B.C.]. Upon the first day therefore of the world, or Octob. 23. being our Sunday, God, together with the highest Heaven, created the Angels. Then having finished, as it were, the roofe of this building, he fell in hand with the foundation of this wonderfull Fabrick of the World, he fashioned this lowermost Globe, consisting of the Deep, and of the Earth; all the Quire of Angels singing together and magnifying his name therefore … And when the Earth was void and without forme, and darknesse covered the face of the Deepe, on the very middle of the first day, the light was created; which God severing from the darknesses, called the one day, and the other night.
— James Ussher