Thales of Miletus, the first known Greek philosopher, seeks rational answers to questions about the world we live in.

Birth of Pythagoras, the Greek thinker who combined maths and philosophy.

Traditional birth date of Kong Fuzi (Confucius), whose philosophy is centred on respect and tradition.

The powerful city state of Athen adopts a democratic constitution.

Death of Siddhartha Gautama, founder of Buddhism

Birth of Socrates, whose methods of questioning is Athens for the basis for much of later Western philosophy

Empedocles proposes the theory of the four Classical elements (earth, wind, fire, water). He is the last Greek philosopher to record his ideas in verse.

Defeat in the Peloponnesian Wars leads to the decline of Athens' political power.

Plato founds his hugely influential Academy in Athens

Aristotle, Plato's student, opens his own school in Athens - the Lyceum

Zeno of Citium formulates his stoic philosophy which goes on to find favour in the Roman Empire.

The death of Alexander the Great signals the end of the cultural and political dominance of Greece in the ancient world.

The death of Aristotle.

Ptolemy, a Roman citizen of Egypt, proposes the idea that Earth is at the centre of the universe and does not move.

Construction of Hadrian's Wall begins, marking the northernmost border of the Roman Empire

Galen of Pergamum provides extraordinary medical research that remains unsurpassed until the work of Vesalius in 1543

The collapse of the Han Dynasty markes the end of the unified China. The Period of Disunity begins.