Holding that there existed a universal principle through which all things are interrelated, a concept he called 'nous,' this ancient opposed the theories of Parmenides who supported the notion of a static universe.  
According to Karl Popper, this pre-Socratic was the chief forerunner of historicism.  Believed to have been heir to a priest kingship, he turned down the post in favor of his brother.  Holding that there existed a universal principle through which all things are interrelated, a concept he called 'nous,' this ancient opposed the theories of Parmenides who supported the notion of a static universe.  The primary advocate of the belief that fire is the one primordial element, FTP, name this philosopher whose most famous aphorism is, "No man can step in the same river twice."
According to Karl Popper, this pre-Socratic was the chief forerunner of historicism.  
Heraclitus of Ephesus