Anaxagoras.-anaxagoras believed that there is an infinite number of elements, and that all things include the essence of all other things. this was in contrast to anaximander, who a century earlier had concluded that there was only one indeterminate primordial substance from which all things are derived. anaximander is believed to have been the first person to attempt mapping the entire world, which he thought of as a stubby cylinder. anaximenes of miletus, a contemporary of anaximander, had taught that all things ultimately consisted of air at various densities. anaximenes of lampsacus (c.380-320 b.c.) was a writer and historian who accompanied alexander the great on his persian campaigns.