Who made people start to believe in evolution?

The original reason for people accepting that evolution had taken place was not the work of any single person. Rather, it was the growing fossil evidence showing that past life had been much different from modern forms. So by the time that Darwin started his work on evolution, it was already a well-accepted reality (in scientific circles at least) that some sort of evolution had taken place.

J.B. Lamarck as well as others proposed various hypotheses about the driving mechanisms of this observed change, but it was Darwin's work that is recognized today as being instrumental in bringing the theory of natural selection to light.

Today, people do not believe in the theory of evolution by natural selection as a result of the work of a single person either: they accept the theory based on the overwhelming evidence supporting it, evidence compiled by many famous or nameless scientists over the course of a century of research.