Tiberius Caesar antedated his reign to a point in time about 10 years before the death of Caesar Augustus.

1. Antedating did occur in the reigns of some first century Roman emperors. Dio describes the reigns of the emperors Galba, Otho, and Vitellius as lasting, respectively, 9 month and 13 days, 90 days, and 1 year minus 10 days (for a total of about 2 years time). Yet he gives the length of time from Nero’s death to the start of Vespasian’s reign (the time frame containing the rules of Galba, Otho, and Vitellius) as only 1 year and 22 days. Dio’s explanation is a classic example of antedating:

“For they did not succeed one another legitimately, but each of them, even while his rival was alive and still ruling, believed himself to be emperor from the moment that he even got a glimpse of the throne.” (Dio, Roman History, 66.17.5)

Though he complains about antedating in the reigns of Galba, Otho, and Vitellius, Dio himself accepts antedating in the reign of Vespasian to a time several months before the death of Vitellius. Furthermore, many modern scholars accepts the idea that Tiberius antedated his reign to a point in time at least a couple of years before the death of Augustus.

2. Tiberius first came to power in the Roman Empire about 10 years before the death of Augustus.

Dr. E. Jerry Vardaman points out a possible starting point for the reign of Tiberius Caesar (Chronos, Kairos, Christos, p. 59-61). About ten years before the death of Caesar Augustus, a grandson of Augustus named Gaius, who had been chosen by Augustus to be the next emperor of Rome, died. Another of Augustus’ grandsons, named Lucius, had also died a couple of years earlier. Tiberius was somewhat in disfavor in the years before the deaths of Lucius and Gaius. He was in voluntary exile on the island of Rhodes and had little power in the Roman empire. But after their death, Augustus chose Tiberius as his successor, adopted him as his son, and gave him a ten-year decree of power. About ten years later, Augustus died and Tiberius succeeded him as emperor of Rome.

At that time in history, it was not uncommon for rulers to date the beginning of their reigns from as early a date as possible, a practice called “antedating.” Therefore, it is possible that Tiberius Caesar also counted the beginning of his reign as emperor from the earliest possible date, from about the time that he was chosen as the heir to the throne and given the name of Caesar.

In the usual chronology, Augustus died in A.D. 14, and the sudden rise of Tiberius to power occurred in A.D. 4. However, the evidence from astronomy places the death of Augustus in A.D. 10, four years earlier. So, in this revised chronology, the death of Gaius and the appointment of Tiberius as the successor to Augustus must also be placed four years earlier, during the year 1 B.C. Augustus appointed Tiberius as his successor by adopting him, on June 26, so that he would inherit the throne. The Roman custom was to count the first full calendar year of an emperor's reign as year one. Therefore, we should count the antedated reign of Tiberius as beginning with the first full calendar year after he was chosen to be the successor to Augustus, which is A.D. 1.

3. A long gap in the account of Josephus
If the first full year of the reign of Tiberius Caesar was A.D. 1, rather than A.D. 11, (the year after the death of Augustus in A.D. 10, by my revised dates), then there was a ten-year overlap in their reigns. This ten-year overlap can be discerned in the writings of the ancient Jewish Roman historian, Flavius Josephus. Josephus is unable to give a detailed description of the first 10 or so years of Tiberius' reign, because he already accounted for the events of those years as a part of the last years of Augustus' reign.

Josephus writes that Valerius Gratus ruled over Judea for eleven years before Pilate, having been sent to Judea at the beginning of Tiberius’ reign. But all that Josephus can tell us about this time period is that Valerius Gratus was procurator of Judea and that he appointed various persons, in succession, as Jewish high priest. Josephus did not have enough material to describe that eleven-year period of time, because he had already described the events of the last ten years of the reign of Augustus (A.D. 1 to 10). Those last ten years of Augustus’ reign coincided with the first ten years of Tiberius’ reign.

The history of the Jewish people, and their interaction with the Romans, was written by Josephus in 20 books (these resemble 20 chapters of one book) called The Antiquities of the Jews. Events occurring during the reigns of Julius Caesar, king Herod, Caesar Augustus, and Tiberius Caesar, are told in this work in significant detail. The time period from the beginning of Herod’s reign over Jerusalem to the completion of the rebuilding of the Temple, a time period of 18 years according to Josephus, is given 425 verses in book 15, an average of 23.6 verses per year. Other books from The Antiquities of the Jews, which cover events from the reign of Julius Caesar to the destruction of Jerusalem, likewise give detailed descriptions of events. The average number of verses per year for each book is listed in the following chart.