Sextus Julius Africanus

Sextus Julius Africanus was an early Christian historian and theologian known as "the father of Christian chronography". He was probably alive in the 2nd or 3rd century CE, which by his reckoning would be around 5700 years after the world's creation. Little of his work survives, but he is chiefly known for his Chronography (in Greek, Chronographiai or Χρονογραφίαι), which provided a complete history of the world from the Creation onwards. This influenced the writings of Eusebius and other later Church historians, despite apparently not being popular enough for anyone to keep a copy or write down any details about Africanus himself.

Life
Who knows?

Extant writings
His surviving writings amount to 16 pages in one fairly recent edition, including editorial notes. Aside from the Chronicles, they include a couple of dubiously-attributed works.

Narrative of Events Happening in Persia on the Birth of Christ
This is commonly reckoned as having been incorrectly attributed to Africanus because it is bollocks. It appears to relate vaguely to the journey of the Magi from the East. Starting in a temple to Juno in Persia, it includes an account of arguing statues, a prophecy about a king of the Jews, the pagan god Dionysus, and a trip to Jerusalem to visit the infant Jesus and Mary.

The passion of St Symphoros and her Seven Sons
He may have written this.

Chronography
His Chronography or Chronicle was the first "universal history" in the Christian church, a big list of everything that had ever happened from the beginning of time. It is perhaps best known for dating the arrival of Jesus's fetus on earth to 5500 years after the creation; this contrasts with the traditional date of creation in the Hebrew calendar of October 7, 3761 BCE; this dating is agreed with Josephus, which he records in Antiquities of the Jews (AJ Preface 13); which is based off an alternate reading which could be found in the Septuagint tradition. However, it is still at odds with modern science.

Africanus attempted to unite Biblical accounts with Greek, Roman, and Jewish history. A major influence was Greek histories and chronicles like the History of Attica by Hellanicus of Lesbos, which covers made-up events like the mythical foundation legend of Athens and real history like the Peloponnesian War. The Greeks were also fond of making lists of priests and priestesses (The Priestesses of Hera at Argon by Hellanicus sounds great fun but is unfortunately now lost) and especially lists of winners of the Olympic Games, in much the same way as the chief literary product of the British Empire is the Wisden Cricketers' Almanack. Everything in ancient Greece is now dated by the Olympiads.

Some excerpts of the Chronography remain, quoted by later writers.
 * He gives a figure of 5500 years from Creation to the Annunciation, which he says is derived from Hebrew histories.
 * A chronology from Adam to Noah. (Seth was born when Adam was 230; Enos when Seth was 205; Cainan when Enos was 190; Malaleel after 170 more years; Jared after 165 years; Enoch after 162; Mathusala after 165; Lamech after 187; Noah after 188.)
 * An account of the Flood dated to when Noah was 600 years old, reckoning 2262 years from Adam to the flood.
 * Abraham entering Canaan in the year 3277 after creation. (There's not a full calculation surviving.)
 * The death of Joseph 3563 years after Adam.
 * The 70 years of Jewish captivity in Babylon ended when Cyrus became king of the Persians, at the same time as the 55th Olympiad (held in 560 BCE by modern reckoning; this is close to modern reckonings of Cyrus's ascent to the throne around 559 BCE ).
 * Some attempt to date early Greek history from Ogygus (or Ogyges), the mythological founder of Thebes, and various other contradictory legends. In his reign, Greece allegedly suffered a flood, claimed by Africanus to be contemporaneous with the Exodus. The Greeks dated 1020 years from Ogygus to the first Olympiad, giving (according to Africanus) 1237 years from Ogygus to Cyrus (which we can calculate puts Ogygus around 1796 BCE). Africanus likewise dates 1020 years from Moses to the first Olympiad, traditionally reckoned at 776 BCE. (Elsewhere, Africanus states that the first Olympiad recorded was actually the 14th, so you might want to add 52 years.) Curiously, Africanus does not reckon Ogygus's flood to be the same as the Big Flood in the Bible, presumably because that chronology would not work. Other sources date Ogygus's flood to 9500 BCE (in Plato), 2136 BCE (Varro's chronology), and 1793 BCE (Africanus).
 * Some stuff about the Prophecy of Daniel, a mysterious part of the Old Testament which Christians will use to, depending on reckoning, give a figure of 70 weeks or 490 years till Jesus's death. He reckons 475 Roman years from Nehemiah to the time of Jesus Christ, the 2nd year of the 202nd Olympiad and the 16th year of Tiberius Caesar (30-31 CE). That equates to 490 Hebrew years because their calendar is lunisolar.
 * Some boring stuff about Herod, Augustus, Antony, etc.
 * He briefly attacks the notion that the darkness at Jesus's death was an eclipse of the Sun because of the obvious astronomical impossibility of an eclipse at Passover but overcame his objections to date the Crucifixion to Passover on the 2nd year of the 202nd Olympiad as above. (Of course, it's entirely possible that the darkness at Jesus's death never occurred. Our article Resurrection of Jesus goes into much more detail.)
 * He claims the Egyptian chroniclers confused months and years in reckoning their own antiquity, which allows him to rearrange ancient Egyptian chronology.