Why was Alfred Russell Wallace significant to Darwin?

Alfred Russell Wallace is significant to Charles Darwin primarily because he encouraged Darwin to publish his ideas about natural selection. Wallace independently conceived the theory of evolution through natural selection while conducting research in the Amazon and the Malay Archipelago. In 1858, Wallace sent Darwin a letter outlining his findings and theories, which prompted Darwin to finally present his ideas to the scientific community. Wallace's letter not only validated Darwin's thoughts but also acted as a catalyst for Darwin to publish "On the Origin of Species" in 1859. This collaboration, although initially unplanned, was crucial for the broader acceptance of evolutionary theory.