Cultural diffusion, as defined by Leo Frobenius in his 1897/98 publication Der westafrikanische Kulturkreis, is the transfer of cultural objects—such as ideas, styles, religions, technologies, and languages—between individuals, whether within the same culture or between cultures. This concept is relevant to cultural anthropology and cultural geography. It is not the same as inventions spreading inside a certain culture. The invention of the war chariot and iron smelting in antiquity, as well as the use of cars and Western business suits in the 20th century, are examples of dissemination. There are now five main categories of cultural diffusion defined: An innovation or concept that emerges in a source location, grows there, and diffuses to other areas is known as expansion diffusion. Diffusion can occur in hierarchical, stimulatory, or infectious ways. Diffusion by relocation: an invention or concept that spreads to new regions while leaving its original place or the source of a cultural characteristic behind. An idea or innovation that moves from larger to smaller locations, frequently without consideration for distance, and frequently influenced by societal elites is known as hierarchical diffusion. An innovation or concept that spreads through person-to-person interaction within a population without respect to hierarchies is known as contagious diffusion. There are now five main categories of cultural diffusion defined: Prior to spreading outward (contagious diffusion), HIV/AIDS originally spread to urban communities (hierarchical diffusion). An innovation or idea that proliferates because it is associated with another concept is known as stimulus diffusion. happens when a particular concept is accepted but the fundamental idea is rejected. Only after coming into contact with domesticated cattle bred by cultures to their south could the early Siberian people domesticate reindeer. They had no use for cattle, but they were drawn to the notion of domesticated herds, so they started domesticating reindeer, an animal they had been hunting for a long time.