The point is not that there were necessarily multiple movements that merged into one; rather, it is that there is no reason to rule it out. It is entirely poss

The point is not that there were necessarily multiple movements that merged into one; rather, it is that there is no reason to rule it out. It is entirely possible that Jesus is a legendary figure based on various Jewish religious leaders with similar messages. The teachings attributed to Jesus are for the most part variations on Jewish precepts and religious themes; even the baptism, which scholars seem to insist was historical, is just a variation on Jewish bathing rituals (mikvah). So we have a man with a relatively generic Jewish name (i.e. Joshua, which in Aramaic is Yeshua or Yeshu, which in Greek is Jesus), who led one of a large number of Jewish cults based on variants of common Jewish religious themes, engaged in common Jewish practices, and was executed by an oppressive occupying force known for its cruel executions of Jewish leaders (see e.g. the "ten martyrs" of the Talmud). Why are we assuming that is a story about specific and real person? Tacitus makes a vague reference to a "cristus" that could have referred to any messianic claimant (as "christ" is just a Greek word for "messiah"), and Josephus makes a similarly vague reference to people with very common Jewish names (Joshua i.e. Jesus, Jacob i.e. James). In both cases there are reasons to doubt that the references refer to the specific Jesus in the biblical or quranic accounts (the latter unquestionably having been written centuries after Jesus supposedly lived). In both cases the claims are not based on the authors' first-hand knowledge and the authors based their writings on what the earliest Christians had told them, something that may have already been merely a legend. Again, it is possible that Jesus was really a person who led a religious movement two thousand years ago. I am only saying that other explanations cannot be ruled out because there is almost no evidence at all. At best all we can say is that the earliest Christians lived about two thousand years ago and by that point believed some version of the Jesus narrative. Beyond that I am not seeing the evidence for a historical Jesus.