I read an article about the historicity of Jesus which concluded that there is very strong evidence that he did in fact live. It didn't seem to have a religious agenda (it was in the Guardian) and it seemed to me like a trustworthy article.
In that article it presented the fact that sources wrote about him only 25 years after he died as good evidence for him existing.
I'm not a historian, but to my lay instinct, it seems weird that someone so famous wasn't written about earlier - perhaps even when he was still alive.
So my question is this: are there other figures in history who are uncontrovertially accepted as real, who we have no evidence of apart from writings long after they died? Without getting into the religious side of things, from a historian's perspective, why does the evidence point to Jesus being a true historic figure? Finally, why could it be that there are no sources closer to his supposed lifetime?
(Somebody would probably turn up and point you to the faq answers on historicity soon enough, here, with answers by myself and /u/jasoncaspian.)
25 years, and
I'm not a historian, but to my lay instinct, it seems weird that someone so famous wasn't written about earlier - perhaps even when he was still alive.
Yes, that would be weird. But Jesus wasn't that famous in his lifetime. While the gospel narratives certainly do portray Jesus at times speaking to large crowds, and being well-known, this primarily happens in the context of rural Galilee and to a lesser extent Judea. His impact, in his lifetime, on literate urbanites appears minimal. And in terms of the Roman empire, he lives on the fringes, far removed from significant events and people. Almost all the "fame" we attribute to Jesus occurred after his death.
If you were looking for an analogy, you would be looking for someone who was locally famous, largely by word of mouth, in a rural setting - an artist for instance, whose works then became famous after their death. Naturally, you would not expect a lot of written evidence about them during their life, since they weren't famous then.
The 25 years thing also makes relatively good sense in its context. No one in broader society has any significant historical interest in writing about Jesus at the time, but the birth and growth of the Jesus' movement makes both the movement itself, and Jesus, more significant.
Within the early church then, you get several impulses towards writing. For example, the development of christian communities in different urban centres creates the conditions for writing between communities, and leaders and communities, which occasions Paul's writings. The generational gap as eye-witnesses of Jesus' life and deeds become older, and the numerical gap as more people join this new religious movement, acts as an impulse towards turning oral recollections and traditions into written texts - the gospels, and later Acts.
It takes a bit longer before non-Christians think that Christians are significant enough to mention in their narratives, but that's when you get mentions of Christians, and Jesus, in texts produced by non-Christians. Josephus, for instance, and the few mentions in early Roman texts like Tacitus, and of course Pliny's letter.
Finally, why could it be that there are no sources closer to his supposed lifetime?
All sorts of reasons. There may never have been such sources, no one may have written such texts. Or they may have been written and never survived. Perhaps some texts were written and didn't achieve wide enough popularity to be copied a lot. Absence of data is hard to explain, because it's arguing from negatives - should there be more data? One can't assume that there should have been texts that are lost. It's much less speculative to consider what data there is and then what historical explanation best explains that data.