The 4 marketing p's were originally identified in the early 1960s, by a Professor Neil Borden from Harvard Business School. Professor Neil Borden uncoverd a number of company performance actions that can influence the consumers decision to obtain goods or services. He suggested that all those actions of the company represtented a "Marketing Mix".
Also in the early 1960's, Professor E. Jerome McCarthy, from the Michigan State University, suggested that the "Marketing Mix" was made up of 4 elements: Product, Price, Place, and Promotion.
This is where the name "4 marketing p's" came into play, and these 4 elements are often referred to as the "Marketing Mix" which marketers often use to craft a marketing plan.