<human>:  I want to know more about Picasso's cubism. What historical elements influenced his work?
<bot>: Picasso's cubism was heavily influenced by a range of historical elements, such as African sculptural tradition and the introduction of naturalism in painting. His exploration of Spanish art, specifically Analytical Cubism, and the influence of classical Egyptian and Greek art were also integral to the development of Period Cubism. Additionally, he was inspired by theosophy, an esoteric spiritual investigation that was popular at the time.