When was Jesus born? Does anyone actually know? Not really, but perhaps an educated guess can be made. Let's take a crack at it...
There is no precise date given in the Bible, only some allusions that point to the general time. Extra-biblical history of the period offers no more than allusions as well. Most historians date Herod the Great's death in the spring of 4 BC; therefore, they place the birth of Christ sometime before that because of the slaughter of the innocents and the recall of the holy family from Egypt. Certainly makes sense.
Yet other historians, like W. E. Filmer, date Herod's death in 1 BC, and for what seems to me very good reasons. Either theory has arguments that can be made, but I think the 1 BC date is more likely and fits the accounts in the gospels better. Rather than words on a page, it's the astronomical phenomenon present at the time in question that tip the scale (and no, that's not a reference to Libra). As I see it, there are two groups and one singular occurrence of astronomical events which set not only the timeline for Herod's death, but also the birth of Christ, his presentation at the Temple, the visit of the Magi, the escape of the holy family to Egypt, and the slaughter of the innocents.
The first group of events was the triple conjunction of Jupiter and Saturn in 7 BC with Venus joining in a close grouping with those two within the constellation Pisces in 6 BC. The Magi, from their likely location in Mesopotamia, would have seen all this and would have interpreted it according to their astrological symbology. Jupiter would have been seen as a sign of significant change in kingly power; Saturn in terms of possible misfortune; Venus, queen of heaven as an omen of fertility and thus birth; Pisces the fishes, as the “House of the Hebrews.”
Specifically, the events in this first group came about as follows:
- On May 29, 7 BC, Jupiter passed Saturn, the first of three conjunctions
- On September 30, 7 BC, Jupiter retrograded past Saturn for the second conjunction
- On December 5, 7 BC, Jupiter repassed Saturn for the third conjunction
- Late in April 6 BC, a close grouping of all three planets became visible within Pisces.
- On September 11, 3 BC: Jupiter passed by Regulus ("King Star") in the constellation Leo for the first conjunction
- On February 17, 2 BC: Jupiter retrograded past Regulus for the second conjunction
- On May 8, 2 BC: Jupiter passed by Regulus again, completing a "circling" of the "King Star"
- On June 17, 2 BC: Jupiter and Venus had an extraordinarily close conjunction, to the point of looking as if the two were one very bright object in the evening sky (the west).
- In the area of Bethlehem shepherds were abiding with flocks overnight, which occurs during lambing season (generally in March/April) in 2 BC
- The birth of Christ occurred sometime near the end of April, 2 BC (May 8th at the latest)
- Mary and Joseph remained in the area at an unnamed house for 8 days until Jesus' circumcision was done and another 33 days for postpartum purification according to the Law (40 days total)
- The Magi visited on June 17, 2 BC by following the star they had seen in the east (Jupiter). It was now incredibly brighter (due to the close conjunction with Venus) and could easily been perceived as aligning over the house were the holy family was staying
- Joseph, warned in a dream, escaped to Egypt with family very soon after the Magi's visit
- When the Magi didn’t report back to Herod, he had all the males born after the star was first seen (September 11, 3 BC) slaughtered, to be sure, he killed any male under 2 yrs of age born there
- Herod died before Passover in 1 BC, after the lunar eclipse in January fitting Josephus' details
- The holy family was given the okay to return home in a dream some time shortly after Herod's death.