What we Know about Jesus of Nazareth

What we Know about Jesus of Nazareth
What is the most important fact of ethical and general philosophical consequence that we know about Jesus of Nazareth, and many other historical figures, including other primary religious figures.
It is probably the fact that we know nothing at all about him.
All we do know, is what has been written about him by authors at a later date, who may not all have had acquaintance with him directly.
The importance of this fact is in it making any positive statement about him illegitimate.
And we do not even have more than an overview of his 'sermons' with his ethical philosophy, which may not be correctly summarised in all instances.
What is hoped about him and other figures in the guise of 'faith' is what it says and no more.