Thallus was a historian who wrote a three-volume history of the Mediterranean world in the mid-1st century AD. Unfortunately, none of his original works have survived, but fragments of his writings are preserved in the works of later authors who quoted him.

One such reference is made by the Christian historian Julius Africanus in the 3rd century AD. In his work "Chronography", Africanus quotes Thallus as having written about the darkness that occurred during the crucifixion of Jesus, and he suggests that Thallus attributed the darkness to a solar eclipse. However, Africanus also notes that this explanation is implausible, since a solar eclipse could not have occurred during the full moon of the Passover festival, which is when Jesus was crucified according to the Gospels.

Africanus then goes on to say that Thallus also wrote about an earthquake that occurred during the crucifixion, which he describes as a "great earthquake" that took place in "Bithynia and other regions". However, Africanus himself casts doubt on this claim, stating that the earthquake was "in my opinion, clearly shown to be erroneous" because it did not occur in the vicinity of Jerusalem, where the crucifixion took place. Whether Thallus was speci cally discussing the cruci xion darkness or a nearby eclipse is debated, but the fact that he tried to provide a naturalistic explanation for a widely reported darkness event is itself evidence that something unusual was being discussed