The word "Renaissance" means "rebirth" — a re-discovery of the art, philosophy and science of ancient Greece and Rome after a period in which that knowledge had been largely preserved only in monasteries and Islamic scholarship. But calling it merely a rebirth undersells it: what happened between roughly 1400 and 1600 was genuinely new.
Florence: the cradle of the Renaissance
The Renaissance started in the Italian city-states, particularly Florence, where wealthy merchant families — above all the Medici — became patrons of artists and scholars. Money flowed into painting, sculpture, architecture and literature. Competition between patrons drove quality. Florence in the 15th century was probably the most artistically productive city in history per capita.
The idea that changed everything: humanism
Renaissance humanism was not atheism — most Renaissance thinkers were Christian. It was the idea that human beings, and not only God, were an appropriate subject of serious study; that this world, not just the afterlife, deserved attention; that reason and evidence could tell us things about nature that authority alone could not.
The key figures
Leonardo da Vinci (1452-1519): Painter, sculptor, architect, musician, mathematician, engineer, inventor, anatomist, geologist. His notebooks contain designs for flying machines and solar power centuries before they were built.
Michelangelo (1475-1564): The Sistine Chapel ceiling. David. The Pietà. The capacity to make marble appear to breathe.
Gutenberg: The printing press (1440s) made the Renaissance ideas reproducible at scale. Before it, a book cost what a craftsman earned in a year. After it, ideas could spread across Europe in weeks.