No surviving source is a contemporary, independent account of Jesus’ life. On this site’s chronology, the earliest recoverable evidence for Jesus and letters attributed to Paul appears with Marcion around 144 CE; the first-century dates assigned to those texts are reconstructions.
The mythicist reading
Mythicists argue that the earliest evidence fits a movement that began with a heavenly or scriptural Christ and was later narrated as an earthly teacher. The late and mediated nature of the sources makes that model possible, and the evidence does not provide the kind of independent biography often assumed in popular accounts.
The strongest reply
The counterargument is that, if the conventional dates and attributions are accepted, the letters, Josephus, and Tacitus are commonly read as evidence for a first-century founder. Mythicism is a minority position, and its proposed origins remain contested.
Where the evidence leaves us
The case turns on how much weight to give indirect, theological, and later sources. The evidence is sparse; the interpretation is disputed. This site argues that the historical-person hypothesis has not been demonstrated by the surviving record.