As there is little recorded history on the early years of Socrates, he is often thought to have studied the doctrines of Parmenides, Heraclitus, Anaxagoras, who were early Greek philosophers. It is clear that these were early influences to the young Socrates and that he used their teachings as a basis for his own.
Socrates was one of the few philosophers in history to be recognized for his work during his own lifetime. Even the Oracle of Delphi pronounced him the wisest man in Greece, for which Socrates was modest in accepting, saying he was only able to recognize his own ignorance.
The influence of Socrates on his fellow Greeks cannot be measured. Plato, his most famous student, worshiped Socates and was the primary author of his life and times. Plato would go on to cite Socrates in his future works and with future students, such as Aristotle.
The influence of Socrates on modern society is also another factor that is hard to measure. Here was a man who was the ultimate example of a person who lived by his principles, even though it ultimately cost him his life. Few of us could say the same about the depth of our own convictions. Even twenty-four centuries after his death, Socrates is still influencing philosophers and students of morals and ethics.
It is clear that the future ages to come will still recognize this small, diminutive man from a long gone culture, for his visionary insights on our personal convictions. Those who sell out quickly for a quick buck, or "sell their souls", to get ahead, should take into consideration that the great Greek philosopher gave his life standing up for what he believed in. This is something that few of us would do.