The Birth of Christ

"... The theologically decisive and interesting point is not the fact that goes back to Dionysius Exiguus, that the birth of Christ was taken as the starting point of subsequent enumeration.... The decisive thing is rather the practice, which has been in vogue only for the last two centuries, of numbering both forward and backward from the birth of Christ. Only when this is done is the Christ-event regarded as the temporal mid-point of the entire historical process.
We say "Christian system of reckoning time." But it is the common system in the Western world.... Yet today scarcely anyone thinks of the fact that this division is not merely a convention resting upon Christian tradition, but actually presupposes fundamental assertions of New Testament theology concerning time and history."

Oscar Cullmann Quoted by Anthony A. Hoekema, The Bible and The Future, p. 28