The Lyceum was already full of footsteps in 335 BC, Aristotle pacing beneath the colonnade in Athens while Theophrastus and Eudemus gathered round him. He had rented the building because, as a metic, he could not own property there, and for twelve years he taught, wrote, and built a library of manuscripts, maps, and museum objects that fed his school of the Peripatetics.

He had come a long way from Stagira in northern Greece, where he was born in 384 BC, the son of Nicomachus, physician to King Amyntas of Macedon, and Phaestis. Both parents died while he was still young, and Proxenus of Atarneus became his guardian. That early link to medicine stayed with him, and so did the habit of watching living things closely.

At seventeen or eighteen he went to Athens and entered Plato’s Academy, where Plato nicknamed him the mind of the school. He stayed nearly twenty years, learning how to argue, classify, and question. In Assos and later on Lesbos, with Theophrastus beside him, he studied botany and marine biology, married Pythias, Hermias’s adoptive daughter and niece, and had a daughter also called Pythias.

Then Philip II of Macedon summoned him to Pella in 343/42 BC to tutor the thirteen-year-old Alexander the Great. At Mieza, in the gardens of the Nymphs, Aristotle taught ethics, politics, Homer, and Euripides. He gave Alexander an annotated Iliad, and some of the prince’s later confidence in eastern conquest carried the mark of those lessons.

After Philip’s assassination in 336 BC, Aristotle returned to Athens for the second and final time and began his most productive years. Between 335 and 323 BC he composed treatises such as Physics, Metaphysics, Nicomachean Ethics, Politics, On the Soul, and Poetics. He was not writing for public display, but for students, and only about a third of his original work survives.

What he left behind was a mind bent on causes. He gave the earliest systematic study of logic, described the four causes, and argued that knowledge means understanding why a thing is so. In biology he recorded around 500 animal species, dissected a fertilised hen’s egg, and drew conclusions from Lesbos and the catches of fishermen rather than from guesswork alone.

The final turn came in 323 BC, when Alexander died and anti-Macedonian feeling surged in Athens. In 322 BC, Demophilus and Eurymedon the Hierophant denounced Aristotle for impiety. He fled to Chalcis in Euboea, saying he would not allow the Athenians to sin twice against philosophy, a bitter echo of Socrates’ death.

He died there later in 322 BC of natural causes, having named Antipater as his chief executor and asked to be buried beside Pythias. His papers passed to Theophrastus, then to Neleus of Scepsis, and from hidden manuscripts to the books that shaped Thomas Aquinas, Peter Abelard, and the modern world.

The man from Stagira did not merely survive in libraries. He became the first teacher, the philosopher, and, in another age, the first scientist.