Lets not forget that St Paul saw the Risen Lord, and he also was given a specific task by the Holy Spirit to explain the theology of what had happened in the Paschal mystery.
As far as the historical Jesus is concerned, here is a passage from St John Paul 2’s Apostolic Letter “Tertio millenio Adveniente” of 1994:
This “becoming one of us” on the part of the Son of God took place in the greatest humility, so it is no wonder that secular historians, caught up by more stirring events and by famous personages, first made only passing, albeit significant, references to him. Such references to Christ are found for example in The Antiquities of the Jews, a work compiled in Rome between the years 93 and 94 by the historian Flavius Josephus,(4) and especially in the Annals of Tacitus, written between the years 115 and 120, where, reporting the burning of Rome in the year 64, falsely attributed by Nero to the Christians, the historian makes an explicit reference to Christ “executed by order of the procurator Pontius Pilate during the reign of Tiberius”.(5) Suetonius too, in his biography of the Emperor Claudius, written around 121, informs us that the Jews were expelled from Rome because “under the instigation of a certain Chrestus they stirred up frequent riots”.(6) This passage is generally interpreted as referring to Jesus Christ, who had become a source of contention within Jewish circles in Rome. Also of importance as proof of the rapid spread of Christianity is the testimony of Pliny the Younger, the Governor of Bithynia, who reported to the Emperor Trajan, between the years 111 and 113, that a large number of people was accustomed to gather “on a designated day, before dawn, to sing in alternating choirs a hymn to Christ as to a God”.(7)
I hope that helps a little!