Possible Clues:

• Year not designated as such until centuries later
• Immaculate Conception year
• Astronomers' 'year zero'
• Prelude to a historic turning point
• Divine conception year
• When Ovid wrote 'Ars Amatoria'
• Yr. before a historic time change
• Last year before the first century A.D.
• Last year of its kind
• When Christianity was 'conceived'?