Aristotle was born in 384 B.C. in Stagira, a small town in Thrace. His father, Nicomachus, was a famous doctor who served as personal physician to King Amyntas II of Macedonia and had many connections at the royal court. It appears likely that Nicomachus played an important part in Aristotle's early intellectual development, encouraging his interest in biology and other natural sciences, and perhaps also training him in medicine.
After the deaths of both his parents, Aristotle went to Athens at the age of 17 to study at Plato's Academy. He remained there for nearly 20 years, toward the end supporting himself as a teacher of rhetoric. There were many popular stories in ancient times about personal conflicts between Plato and Aristotle during this period, but they have no factual basis and seem to have been prompted by Aristotle's later opposition to many of Plato's doctrines. Aristotle was very much under Plato's influence while studying at the Academy and his earliest written works were dialogues patterned after those of Plato and expressing conventional Platonic philosophical ideas. Even many years after Plato's death, when he was fully established in his own right as the head of a philosophical school, Aristotle continued to remember his teacher with the warmest affection and respect, as is shown by his comments in the first book of the Nicomachean Ethics.
Nicknamed "the mind" and "the reader" by Plato, Aristotle rapidly became one of the most outstanding students at the Academy. When Plato died in 348 B.C., his nephew Speusippus was appointed head of the school. Having no personal loyalty to Speusippus and disagreeing with his tendency "to turn philosophy into mathematics," Aristotle decided to leave Athens. Some scholars have suggested that he resented not having gotten the post which Speusippus inherited.
Accompanied by a few other students, Aristotle went to Atarneus, a small city on the western coast of Asia Minor, which was governed by Hermias, a former student at the Academy with whom he was friendly. Aristotle married Hermias' niece and established his own school at Assos, near the site of ancient Troy, on land Hermias gave him.
A few years later, Hermias was overthrown and murdered by a pro-Persian faction. It was no longer safe for Aristotle to remain at Assos, so he took his family to Mytilene on the island of Lesbos, the home of Theophrastus, another friend from his Academy days. Aristotle spent the next three years there, collecting data for his studies in biology. It is widely believed that he used this interlude for rethinking his whole philosophical position and had completely broken with Plato's system by the time he left Lesbos.
In 343 B.C., King Philip of Macedonia invited Aristotle to act as tutor to his 13 year old son Alexander. Still under Plato's influence to the extent that he thought it important to teach philosophy to princes, Aristotle immediately accepted the offer and moved with his family to Pella, the Macedonian capital. He lived there for almost eight years, but served as tutor for less than four because Alexander was soon called on to act as regent for his father and could spare little time for academic studies. The philosopher and his pupil are said to have become good friends, but in view of Alexander's later career and ideas, it is thought that Aristotle's teaching made no lasting impression on him.
Philip was assassinated in 335 B.C. and Alexander became King. After a quick pacification of the Greek states, he set out on his famous campaign against the Persian Empire. Several of Aristotle's students accompanied the victorious army to do research in the strange new lands of the east, and with Alexander's cooperation sent back at regular intervals written reports on their findings, as well as samples of plants, animals, minerals and anything else of interest.
Meanwhile, Aristotle returned to Athens, where he founded his own philosophical school at the Lyceum, a public garden and gymnasium dedicated to Apollo, which soon became known as the "peripatetic" school because of the peripatos or covered walk where he strolled each morning with his students while lecturing on various subjects.
Aristotle remained in Athens for 12 years, during which he did his most important writing and teaching. In all disciplines he emphasized empirical research and the accumulation of data before drawing conclusions, and the Lyceum was noted, among other things, for its library and zoo, both of which were valuable adjuncts to this aspect of his teaching. The Lyceum soon came to rival the Academy, and continued in existence as a school for nearly 800 years.
When Alexander died in Persia in 323 B.C., a wave of anti-Macedonian feeling swept through Athens and the rest of Greece. As Alexander's tutor and friend, Aristotle was one of its first victims. He was charged with impiety and brought to trial, more for political than religious reasons. To prevent the Athenians "from sinning a second time against philosophy," as he explained with an allusion to the fate of Socrates, Aristotle took his family north to Chalcis, his mother's birthplace, where he owned an estate. He died there soon afterwards in November, 322, at the age of 62. His old friend Theophrastus succeeded him as head of the Lyceum and continued his work in Athens, while his son Nicomachus along with some other students devoted themselves to compiling and editing his lectures.