Introduction: How do Biblical chronologists determine when events occurred during New Testament times? The main approach is to relate the dates of events in the life of Christ and in the early Church to dates of events in Roman and Jewish history.
An Example: Christ was crucified when Pontius Pilate was ruler over Judea. According to Josephus, Pilate had a ten-year reign which ended about the time that Tiberius Caesar died (Ant. 18.89). If we can determine when Tiberius died, then we can determine the date range for Pilate's reign over Judea. The date of the Crucifixion must fall within that range of dates.
The Problem: Most current theories about the date of the Crucifixion assume the generally-accepted dates for Tiberius' death and Pilate's reign over Judea. They do not prove or support this assumption with evidence. And they summarily dismiss any challenges to these generally-accepted dates on the grounds that the vast majority of scholars accept these dates.
The same is true for nearly every theory or set of dates related to New Testament Biblical chronology. Biblical chronologists begin by assuming the generally-accepted dates for events in Roman history, especially the dates of the reigns of various Roman emperors. If those dates are incorrect, then the foundation of nearly every modern theory of New Testament Biblical chronology crumbles to the ground. Biblical chronologists realize their dependency on the generally-accepted dates in Roman history, and so, they shrewdly refuse to even consider any theory which, if proved correct, will cause their own theories to fall apart.
When I first began my work in Biblical chronology, I too assumed the usual dates for events in Roman history. Then I noticed that Cassius Dio described a solar eclipse seen by the Roman people prior to the death of Augustus. With modern computer software, it is easy to determine the dates for past solar eclipses, even going back 2,000 years. Using a program called RedShift 3, I looked for a solar eclipse in the year A.D. 14, the generally-accepted year for the death of Augustus. In that year, there were no solar eclipses visible from anywhere in the Roman empire. I checked the accuracy of the software against charts of solar eclipses, lunar eclipses, and lunar phases available on the following web sites. As it turns out, the software is accurate.
Five Millennia Catalog of Phases of the Moon: -1999 to +3000
Five Millennium Catalog of Lunar Eclipses: -1999 to +3000
Six Millennium Catalog of Solar Eclipses: -1999 to +4000
For further references and much more detailed information, see the book Important Dates in the Lives of Jesus and Mary, available in paperback. The book and this web site are both copyrighted by Ronald L. Conte Jr. Much of the text on this site is taken from the book. Brief quotes with proper attribution are permitted.
In fact, there were no solar eclipses visible from anywhere in the Roman empire in A.D. 11, 12, 13, and 14. In A.D. 10, there was a solar eclipse which fit Dio's description. I began to wonder whether Augustus might have died in some year other than A.D. 14. I undertook a study of eclipse and comet sightings in the writings of the historians of that time period (including Dio, Tacitus, Suetonius, Pliny, and Josephus). The Romans were somewhat superstitious about eclipses and comet sighting, thinking them to be portents of future events. The Roman historians, therefore, often mention eclipse and comet sightings in conjunction with major historical events.
The dates of solar eclipses are very helpful in determining the dates of historical events during this time period, because solar eclipse sightings are common enough to be seen and mentioned numerous times in Roman history, but not so common that any set of dates for events could fit the mention of a solar eclipse. Lunar eclipses are not as helpful, with a few exceptions, because lunar eclipse sightings are much more common than solar eclipse sightings.
Comet sightings are often mentioned by Roman historians in conjunction with historical events. Such sightings are useful because there is often a description of the comet's appearance which can be compared to the dates and descriptions of comets in the records of ancient Chinese and Korean astronomers. They were the best astronomers of ancient times and kept careful records. Information on ancient comets is found in the book Cometography by Gary Kronk.
After several years of research, I concluded that the generally-accepted dates for events in Roman history, for the first century B.C. and first century A.D., are incorrect. A revised chronology of Roman history for that time period based on the evidence of eclipses and comet-sightings, is presented as part of my book, Important Dates in the Lives of Jesus and Mary.
Additional evidence, not based on eclipse and comet sightings, also supports this revised chronology.