Fragment 15
And Africanus, in the third book of his History, writes: Now the first Olympiad recorded— which, however, was really the fourteenth— was the period when Coroebus was victor; at that time Ahaz was in the first year of his reign in Jerusalem. Then in the fourth book he says: It is therefore with the first year of the reign of Ahaz that we have shown the first Olympiad to fall in.
Source: Extant Writings (New Advent)