No records for Jesus’s existence survive from the period before his death, which has been presumed as being in 33CE.
The earliest source is the letters (epistles) of St Paul, dated to 59 CE, who first detailed his crucifixion. The few mentions of him in non-Biblical sources, by the Roman historians Josephus and Tacitus, are even later.
Despite this, most historians accept that there was a historical figure Jesus Christ. Academics studying the evidence for the life of Christ accept, through this process of comparison and using evidence from the time not related to his life.
It is also known that this was a period in which many inspirational preachers appeared in Palestine. It has been proposed by some historians that the character of Jesus might have been an amalgam of different real preachers, although the prevailing view remains that there was a historical Jesus, although we do not, and may never, know much more about him.