Who initiated numbering the years of the calendar from when Christ was believed to have been born?

I'm reasonably certain that when Christ was crucified, his disciples didn't say, ';Here it is, A.D. 33.'; I've asked many people and checked several encyclopedias, but no one has been able to give me the answer to the above question.Who initiated numbering the years of the calendar from when Christ was believed to have been born?
In ancient times, calendars were generally renumbered with each new ruler, so it was not without precedent that around what is now known as A.D.525, a monk named Dionysius Exiguus proposed that years be counted from the birth of Christ. This was adopted throughout the Christian world over the following 500 years. Modern chronologists, however, position the occasion closer to 4 B.C., several years earlier.Who initiated numbering the years of the calendar from when Christ was believed to have been born?
Christ actually died on good Friday of 7 ad





33 came about because the calendar system changed many times so people thought that that was the day that he died however science has proven that the time had to be 7 ad ( passover on that day with the king and the eclipse)
Then they must not have looked very hard, because it's an easy get. The system was devised in 525 by Dionysius Exiguus.
It all started after Babylon A.D.