On another thread on this subreddit, a lot of endorsed contributors and mods claimed that the existence of Jesus has pretty much been 100% established.
Judging by the gospels, Jesus was resurrected after being executed and this is what finally convinced all the apostles to spread the word of Christianity.
Obviously, secular historical analysis probably does not accept that he actually woke up after dying and walked around Jerusalem. Have any historians speculated on what could have actually happened to trigger the apostles and send them across the empire? It seems that something profound happened to them, considering that they were willing to be tortured and killed for their belief. That, to me, shows that either they actually saw something miraculous or believed they did.
So what is the most likely secular explanation for the Resurrection?
In general the secular consensus seems to be that his death, followed by visionary experiences kicked off the early movement, with no resurrection necessary.
The earliest sources we have are the epistles of Paul. They were written before any of the gospels. And they are notable for not having a reference to a "bodily" resurrection. Instead Paul seems to speak of a purely spiritual resurrection. For Paul Christ's spirit assumed his full glory. Paul seems entirely disinterested in what happens to Christ's body. And yet he talks of having talked to Christ and having an experience equal to that of any of Jesus's disciples who knew him in life.
The earliest versions of the earliest gospel, Mark, also leaves off the full resurrection narrative. Mark ends with the angel telling the women that Jesus "is not here" at the tomb. But the women flee without investigating. And the story ends. There is no story about the Apostles or anyone else meeting the resurrected Jesus in the flesh. In fact I've read speculation that this was originally not meant to indicate that his body was gone, but instead that simply his essence no longer resided in his body.
The earliest a physical resurrection seems to enter the story is around 80 or 90 CE. That's when Matthew and Luke were likely penned, with a resurrection narrative in mind. And that also seems to be when Mark's coda was written and appended to his Gospel.
Whatever kicked off the early evangelist zeal of the original band of disciples, and early converts like Paul, seems to be entirely spiritual and visionary. No resurrection was necessary. In fact it doesn't seem like anyone was talking about a resurrection until at least 50 years after the fact.