Though influenced primarily by Socrates, to the extent that Socrates is usually the main character in many of Plato's writings, he was also influenced by Heraclitus, Parmenides, and the Pythagoreans.
It is widely accepted that Plato, the Athenian philosopher, was born in 428-7 B. E and died at the age of eighty or eighty-one at 348-7 B. L.), following Apollodorus' chronology, Plato was born the year Pericles died, was six years younger than Isocrates, and died at the age of eighty-four (D. Diogenes' claim that Plato was born the year Pericles died would put his birth in 429. Diogenes' report that Plato's birth was the result of Ariston's rape of Perictione (D. 3.1) is a good example of the unconfirmed gossip in which Diogenes so often indulges. Plato's actual given name was apparently Aristocles, after his grandfather. Although the name Aristocles was still given as Plato's name on one of the two epitaphs on his tomb (see D. Strabo (17.29) claims that he was shown where Plato lived when he visited Heliopolis in Egypt. In any event, Plato returned to Athens and founded a school, known as the Academy.Plato, perhaps now completely disgusted with politics, returned to his beloved Academy, where he lived out the last thirteen years of his life. His grave, however, has not yet been discovered by archeological investigations. There can be no doubt that Plato was also strongly influenced by Parmenides and Zeno (both of Elea), in Plato's theory of the Forms, which are plainly intended to satisfy the Parmenidean requirement of metaphysical unity and stability in knowable reality.According to Diogenes, Plato was buried at the school he founded (D. Aristotle and Diogenes agree that Plato had some early association with either the philosophy of Heraclitus of Ephesus, or with one or more of that philosopher's followers (see Aristotle Metaph. Parmenides and Zeno also appear as characters in his dialogue, the He mixed together in his works the arguments of Heracleitus, the Pythagoreans, and Socrates. 3.8) A little later, Diogenes makes a series of comparisons intended to show how much Plato owed to the comic poet, Epicharmus (3.9-3.17).Nonetheless, it is plain that no influence on Plato was greater than that of Socrates.This is evident not only in many of the doctrines and arguments we find in Plato's dialogues, but perhaps most obviously in Plato's choice of Socrates as the main character in most of his works.