I feel Protagoras is the best among all. He gave the concept of the theory which is today called as Relativism. He has written a lot of works like: On the Gods and Truth. He was a sophist. He was actively involved in public speaking and teaching the youth on the importance of philosophy. He was great philosopher of his time who had a lot of virtue, knowledge and wisdom. He could be credited for the work of defining the grammatical rules. He was a very religious person whose work was mostly concerned with the gods and religion. He was called at many places so that he could spread his knowledge and wisdom among all the people. His works done were recognized in the world. Many of his tasks have been missing. Even after 2500 years too, people cherish and refer the philosophy of Protagoras. This theory of Relativism is followed today as well even in the modern times. He was a person who established the relation between the god and how truth is essential in order to survive and gain knowledge with time. His work was admired during that time too. He tried establishing his teachings but included people only when they were in full belief of his concepts.