According To The Vice-Chancellor of Cambridge University

If all men and women were descended from Adam and Eve then it was possible 
to calculate how many generations had passed from Adam through the line of 
David down to the period of recorded history  and discover how many years 
humans had lived on the earth's surface... According to the Vice-Chancellor
of Cambridge University (1644) John Lightfoot : 

" Man was created by the Trinity about the third hour of the day, or 
nine o'clock in the morning in the year now identified as 3928 B.C."    

Six years later Archbishop James Ursher did his own calculation and stated 
that the beginning of time fell upon the night before the twenty-third day 
of October in the year of the Julian calendar 710 which is 4004 B.C.