What year was Jesus born?

The "AD" system of dating was developed by a sixth-century monk at Rome named Dionysius Exiguus (or "Dennis the Short" - yes, really) as he worked on a system for setting the date of Easter. Dionysius was brilliant but didn't have great information to work from and he almost certainly got it wrong. The New Testament says that Jesus was born while Herod the Great was king of Judea, but Herod died in 4 BC. IF the New Testament is accurate on that point, then Jesus was born no later than 4 BC and maybe earlier, like 6 BC or so. If it isn't, his birth year might have been as much as ten years later than that.

Also, in the Dionysian system the year doesn't start on January 1. AD - "Anno Domini," the "year of the Lord" - refers to incarnation years. It compares to regnal years; ancient and medieval people would often date events as happening "in the third year of king so-and-so," and that year begins not on January 1 but whatever date king so-and-so began his reign. The idea to an incarnation year is that you're dating the first year of Christ's incarnation, second year, and so forth (which is why there's no year zero). Now, what date to count the incarnation from was taken differently by different writers; a few used Christmas, but most medieval writers assumed that it should be counted from when Christ entered Mary's womb. That was traditionally believed to have happened at the Annunciation, celebrated on March 25 in the church calendar (also believed to have been the date of Christ's crucifixion). Christmas was set at December 25 because 1) it helped it compete with the pagan festival of Saturnalia, which began a few days earlier and ran all week and 2) it was nine months from March 25, the Annunciation.

January 1 was the traditional beginning date of the Roman year and was ignored in the Christian calendar. It wasn't officially adopted as the start date of the new year until the early modern era, in the sixteenth century in some areas but not until the 1750s in others.

Jesus was born when the roman empire was conducting the census most historians think it was 6 bc but there are some think it was 14 ad .

1) Christ was born some time in the spring (probably May) of 4 BC.

- coinciding with the four major planets appearing in the Zodiac sign associated with the Jews; and at a time of the year when the sheep gave birth.

2) The early Christians decided to celebrate His birth on 25 December so as to coincide with the Roman celebration of the Winter Solstice (so they wouldn't "stand out")

3) When the Gregorian Calendar was invented, they called the 1st year 1 AD (rather than 0 AD as it should have been).

He was born in the spring, not the winter solstice. That was set up by the Catholic Church. And he was actually born a little before BC started. It's too long ago and undocumented for a set date.

Many say 4 b.c., the date has never and will never be agreed on.

0 AD

And he wasn't born december 25; he's most likely to have been born in the spring.