Economic theories were created to try to explain certain economic phenomena, that is, to explain why and how the economy behaves. Economic theories are, in fact, a series of assumptions, hypotheses, definitions and instructions on what to do in a particular economic situation. Throughout history, various economic theories have emerged, each typical of the time in which it originated. Each of the theories was created with the purpose of explaining a specific situation or problem that appeared in the economy of that time. There are multiple approaches and schools of taught. Hypotheses interact and are often contradictory in multiple ways. Economics is not a hard science as formal or natural sciences are. As economy develops over time, so does economic theory. Since this is an approach, there will never be a definitive theory, but each theory is precise enough for the period in which it was created and for the purpose at hand. This paper will acquaint the reader with the development of economic thought from antique to the present and clarify the differences between economic thoughts and how they changed based on the development of the economy of a particular period.