The Olympiad Calendar and the Birth Year of Christ

An explanation of the ancient Greek Olympiad system especially as it relates to the birth year of Christ.

This is part of an unfinished series on the problems and evolution of the calendar system and how it effects dating the year of Christ’s birth.

The ancient Greeks used Olympiads as their yearly dating system. The first Olympiad was conducted in 776 BC. It was calculated in four-year intervals.

For example the first Olympiad happened in 776 and the second occurred in 772 BC.

776 BC = Olympiad 1, not 0. Zero as a mathematical number in the Greco-Roman world was a later invention. Using a calculator without this knowledge to validate later dates can throw off any Olympiad by four years.

The four year interval is not specific enough for most historic purposes. Most modern readers want to know the exact year, not that it happened somewhere unspecified in the four year interval. Later writers tended to use an alpha system to demonstrate which of the four years the Olympiad meant, such as the 184a Olympiad, which would be the first year of the 184th Olympiad.

The first century Roman-Jewish historian, Josephus, sometimes used the regnal dating system. This system was popular in ancient times throughout the Mediterranean basin which defined time according to the birth and death dates of a great leader. However, Josephus was conscious of the fact that this was not accurate and combined it with Olympiads and then went a step further and aligned it with historic battles.

The following is an important example of his use of the Olympiad dating system. He wrote that Herod was first given his title as king by Rome on the 184th Olympiad,¹ which translates anywhere between 44/43 and 41/40 BC.

Josephus is the closest historian to the time of Christ and his dates are rarely challenged. There are few other texts outside the Bible and Christian history available with the level of detail that he provides with regards to the Middle East during this time. One must keep in mind though that there are potential manuscript errors. There are many copies of Josephus’ writings with variants in dates and times, though these transcription errors do not directly affect the Herodian calendars, it does raise some suspicions.²

An alternative to Josephus is Julius Africanus. He was a second-century chronicler who gave a detailed account of histories related to the Olympiads. He may be the earliest Christian historian who tried to parallel Greek and Jewish histories according to some sort of timeframe. He critically attempted to establish the first Olympiad and use that as his basis. He believed that before the Olympiad system came into being, a timeline of any history from a Greek perspective could not accurately be deduced.³

In the Africanus account available today, one can find a problem with the Olympiad calculation which was likely related to a transcription error. He wrote, “the 16th year of Tiberius Caesar, which was the second year of the 102d Olympiad”⁴— this would make Tiberius’ reign, based on the 776 BC date, to be approximately 368 BC. Fortunately, the text mentions earlier in the same document regarding Tiberius 16th year as, “the 202d Olympiad”, which made it to be properly around 30 AD.⁵

The eighth-century British-Christian writer and scholastic monk, the Venerable Bede, used Olympiads among many others to define historic time periods, though our present manuscripts attributed to him may contain errors. He recorded the first Olympiad to Julius Caesar to be the 183rd Olympiad–20 years off.⁶

Olympiads were not the dating system of preference by most of the ancient Christian writers and it was not accepted as a universal calendar. Its was a legacy system after the fourth-century AD. However, because of Josephus’ usage, it is an important clue, though not the ultimate one, for the birth year of Christ.

Josephus’ account does not directly address Christ’s birth in his copy, but one can correlate from Josephus’ dated chronology of the Herod family and the Biblical description roughly what year the birth was. For more details on exactly how Josephus and other historians dated these leaders, see:
A Chronology of the Herods

To read more, see the introductory article, What Year was Christ Born? or go to the series Christian Calendar System homepage for a listing of all the articles on the subject.

1. Antiquities of the Jews: XIV:XVI:4
2. William Whiston trans, The Works of Josephus. Massachusetts: Hendrickson Publishers, 1982. “Dissertation V” p. 696
3. IBID, III.-The Extant Fragments of the Five Books of the Chronography of Julius Africanus. XIII:1
4. Extant works of Julius Africanus found at tthp://www.newadvent.org/fathers/0614.htm Fragment 18:2 This may be an error in the English translation or a typographic error. The Greek has not been checked.
5. Extant works of Julius Africanus as found at tthp://www.newadvent.org/fathers/0614.htm Fragment 16:3 .
6. See Bede, De Temporum Rationem, MPL, Vol. 90, pg. 538, especially the footnote b which discusses how Bede missed those 20 years.