of 4004 BC differed little from other Biblically based estimates , such as those of Jose ben Halafta (3761 BC), Bede (3952 BC), Ussher's near-contemporary Scaliger (3949 BC), Johannes Kepler (3992 BC) or Sir Isaac Newton (c. 4000 BC).   By the end of the 18th century, Ussher's chronology came under