It was the first day of the year in the medieval Julian calendar and the nominal vernal equinox (it had been the actual equinox at the time when the Julian calendar was originally designed).Considering that Christ was conceived at that date turned March 25 into the Feast of the Annunciation which had to be followed, nine months later, by the celebration of the birth of Christ, Christmas, on December 25.
Patriarchs from Adam to Terah, the father of Abraham, are said to be older by as much as 100 years or more when they begat their named son in the Greek Septuagint than they were in the Latin Vulgate (Genesis 5; Genesis 11) or the Hebrew Tanakh (Gen 5; Gen 11).
They can be found in the Apology to Autolycus (Apologia ad Autolycum) by Theophilus (AD 115-181), the sixth bishop of Antioch, His chronology begins with the biblical first man Adam through to emperor Marcus Aurelius, in whose reign Theophilus lived.
The chronology puts the creation of the world at about 5529 BC: "All the years from the creation of the world amount to a total of 5,698 years." Dr.
Annianus of Alexandria however, preferred the Annunciation style as New Year's Day, 25 March, and shifted the Panodoros era by about six months, to begin on 25 March.
This created the Alexandrian era, whose first day was the first day of the proleptic This system presents in a masterly sort of way the mystical coincidence of the three main dates of the world's history: the beginning of Creation, the Incarnation, and the Resurrection of Christ.