Scholars who specialise in the origins of Christianity agree on very little, but they do generally agree that it is most likely that a historical preacher, on whom the Christian figure "Jesus Christ" is based, did exist. The numbers of professional scholars, out of the many thousands in this and related fields, who don't accept this consensus, can be counted on the fingers of one hand. Many may be more cautious about using the term "historical fact" about this idea, since as with many things in ancient history it is not quite as certain as that. But it is generally regarded as the best and most parsimonious explanation of the evidence and therefore the most likely conclusion that can be drawn.
The opposite idea - that there was no historical Jesus at all and that "Jesus Christ" developed out of some purely mythic ideas about a non-historical, non-existent figure - has had a chequered history over the last 200 years, but has usually been a marginal idea at best. Its heyday was in the late Nineteenth and early Twentieth Century, when it seemed to fit with some early anthropological ideas about religions evolving along parallel patterns and being based on shared archetypes, as characterised by Sir James Frazer's influential comparative religion study The Golden Bough (1890). But it fell out of favour as the Twentieth Century progressed and was barely held by any scholars at all by the 1960s.
The whole article is quite detailed and very much worth reading. One of the factors that complicates the issue is that there are significant differences between the Jesus of the Gospels and the Jesus of Paul, Christianity's main promoter who never met Jesus in person. Even in the Gospels the nature of Jesus changes substantially, from the itinerant preacher and healer of Mark (~60 CE) to John's "logos" of the entire universe (~130 CE). Furthermore, during that same period Christianity was borrowing ideas from other popular religions of the time such as Mithraism and transforming itself from a radical Jewish sect to a potential world religion in its own right.
Regardless, as the article explains none of these points demonstrate an absence of Jesus from history. They do imply, though, that if he were to return and examine the state of modern Christianity he would be unlikely to recognize many elements of the edifice that has been erected in his name.
