How confident can we be that Jesus Christ actually lived?This article came out for Easter and I'm just now getting to it. It has a good overview of the early historical evidence that Jesus was a real person. This is not in any way controversial. No specialist doubts the existence of Jesus. The historical evidence is ample.
The historical evidence for Jesus of Nazareth is both long-established and widespread. Within a few decades of his supposed lifetime, he is mentioned by Jewish and Roman historians, as well as by dozens of Christian writings. Compare that with, for example, King Arthur, who supposedly lived around AD500. The major historical source for events of that time does not even mention Arthur, and he is first referred to 300 or 400 years after he is supposed to have lived. The evidence for Jesus is not limited to later folklore, as are accounts of Arthur.
A more controversial question is who the historical Jesus was. What did he do, what did he teach, and what kind of religious practitioner was he? For my thoughts on the matter, see here and links.