Charles Robert Darwin FRS (12 February 1809 – 19 April 1882) was an English naturalist who established that all species of life have descended over time from common ancestors, and proposed the scientific theory that this branching pattern of evolution resulted from a process that he called natural selection. He published his theory with compelling evidence for evolution in his 1859 book On the Origin of Species. The scientific community and much of the general public came to accept evolution as a fact in his lifetime, but it was not until the emergence of the modern evolutionary synthesis from the 1930s to the 1950s that a broad consensus developed that natural selection was the basic mechanism of evolution. In modified form, Darwin's scientific discovery is the unifying theory of the life sciences, explaining the diversity of life.