His father contributed all which was necessary to give to his son a good education, and, therefore, Plato must have been instructed in grammar, music, gymnastics and philosophy by some of the most distinguished teachers of his era.
Plato had also attended courses of philosophy; before meeting Socrates, he first became acquainted with Cratylus (a disciple of Heraclitus, a prominent pre-Socratic Greek philosopher) and the Heraclitean doctrines.
Ambrose believed that Plato met Jeremiah in Egypt and was influenced by his ideas.
One story, based on a mutilated manuscript, Although Socrates influenced Plato directly as related in the dialogues, the influence of Pythagoras upon Plato also appears to have significant discussion in the philosophical literature. Hare, this influence consists of three points: (1) The platonic Republic might be related to the idea of "a tightly organized community of like-minded thinkers", like the one established by Pythagoras in Croton.
Pythagoras, or in a broader sense, the Pythagoreans, allegedly exercised an important influence on the work of Plato. (2) There is evidence that Plato possibly took from Pythagoras the idea that mathematics and, generally speaking, abstract thinking is a secure basis for philosophical thinking as well as "for substantial theses in science and morals".
In contrast to reticence about himself, Plato often introduced his distinguished relatives into his dialogues, or referred to them with some precision: Charmides has a dialogue named after him; Critias speaks in both Charmides and Protagoras; and Adeimantus and Glaucon take prominent parts in the Republic.