Citations from Lost Documents.
Citations in writings of the early church Fathers reveal that there were references to Jesus in other secular works that are now lost to us.
The Acts of Pilate
Justin Martyr, in about AD 150, wrote in defense of the Christian faith to the Roman Emperor Antonius Pius:
'And after he was crucified they cast lots upon his vesture, and they that crucified Him parted it among them. And that these things did happen you can ascertain from the Acts of Pontius Pilate.'
And in another place he says:
'That he performed these miracles you may easily satisfy yourself from the "Acts" of Pontius Pilate.'
These 'acts' were official chronicles submitted to Rome by provincial governors. Justin would have been pretty stupid to write something like this to the Emperor if he was not sure of his facts: but he was a very gifted scholar and certainly no fool. Sadly, however, these chronicles have not survived to the present day (a 4th-century document of this name is an acknowledged forgery.)
Opponents try to suggest they were deliberately destroyed: but the simple fact is that there are no surviving documents of this type from any Roman province of that period.
Thallus and Phlegon
Julius Africanus (c.221 AD) tells us that the first century historian Thallus, in the third volume of his Histories, attempted to explain the darkness at the time of Jesus' death in terms of a solar eclipse; though Africanus himself expresses doubt about this theory.
Just after this passage Africanus also makes mention of another historian, Phlegon, who wrote his chronicles (known as the 'Olympiads') about 140 AD. Phlegon is also cited by Origen, as follows:
'Now Phlegon, in the thirteenth or fourteenth book, I think, of his Chronicles, not only ascribed to Jesus a knowledge of future events (although falling into confusion about some things which refer to Peter, as if they referred to Jesus), but also testified that the result corresponded to his predictions. So that, he also, by these very admissions regarding foreknowledge, as if against his will, expressed his opinion that the doctrines taught by the fathers of our system were not devoid of divine power.' ('Against Celsus' 2.14.)
'And with regard to the eclipse in the time of Tiberius Caesar, in whose reign Jesus appears to have been crucified, and the great earthquakes which then took place, Phlegon too, I think, has written in the thirteenth or fourteenth book of his Chronicles.' ('Against Celsus' 2.33.)
'Regarding these we have in the preceding pages made our defence, according to our ability, adducing the testimony of Phlegon, who relates that these events took place at the time when our Saviour suffered.' ('Against Celsus' 2.59.)