Aristotle was born around 384 BC in Stagirus on the Chalcidic peninsula of northern Greece, to Nicomachus, a medical doctor, and Phaestis. Stagirus was his father's home, while Phaestis came from Chalcis in Euboea.
We don't know anything about Aristotle's childhood, but it is likely Nicomachus would have expected his son to follow in his footsteps. So, Aristotle quite probably traveled with his father on his work, which was the way of the physician of the day. Unhappy with the conditions in the region, Nicomachus began traveling and working more in neighboring Macedonia and eventually became the personal physician to Amyntas III, king of Macedonia.
It is unknown whether the family moved to Pella, the Macedonian capital, or whether Aristotle's father moved there for his work. Either way, young Aristotle seems to have at least spent some time there as he became friends with Philip, the king's son, who was about his own age. When Aristotle was around the age of 10, Nicomachus died, ending his plan for Aristotle to take up medicine. Either shortly before or shortly after that time, Phaestis also died, leaving the young Aristotle in the care of an uncle (either by blood or as a family friend), Proxenus of Atarneus. Proxenus continued Aristotle's education by teaching him Greek, rhetoric, and poetry.
Aristotle and PlatoAround the age of 17, Aristotle became a student at Plato's Academy in Athens. While Plato was not there at the time, but on his first visit to Syracuse, the Academy was being run by Eudoxus of Cnidos. Other teachers included Speusippus, Plato's nephew, and Xenocrates of Chalcedon.
Aristotle was so impressive as a student that he soon became a teacher, himself, remaining at the academy for 20 years. While we know little about Aristotle's subjects at the Academy, it is said that he taught rhetoric and dialogue. He probably did teach rhetoric, as during this time he published Gryllus, a tome that attacked Isocrates's views on rhetoric. Isocrates ran another major educational establishment in Athens.
The events leading to Aristotles departure from the academy are a bit cloudy. Some say that after Plato died in 347 BC, Speusippus assumed the leadership of the Academy. Perhaps Aristotle quit because he disagreed with Speusippus's views, or had hoped to be named Plato's successor, himself. Another theory deals with Aristotle's old friend, Philip of Macedonia.
In 359 BC, Philip had ascended to the throne when his older brother, Perdiccas was killed fighting off an Illyrian invasion. Philip was a skillful ruler, who not only maintained peace in his own realm, but also expanded into neighboring territories. Philip captured Olynthus and annexed Chalcidice in 348 BC. Athens was concerned about the threat of an expanding Macedonia. It's possible Aristotles continuing friendship with a threatening ruler may have led to his politically charged departure from the Academy. It also appears that Xenocrates of Chalcedon left with him.