Stone axes were once believed to be thunderbolts fallen from the sky
Sixteenth-century Europeans called the chipped flints scattered across their fields thunderstones, convinced lightning made them. Working out that people had made them, and that stone tools came before bronze and iron, took centuries of guesswork before a Danish museum curator turned the idea of Stone, Bronze and Iron Ages into evidence.
The notion of ages named after materials is ancient. The Greek poet Hesiod, writing perhaps between 750 and 650 BC, described five ages of humankind, golden, silver, bronze, heroic and iron, but as a moral decline: he wished he had not been born into the fifth. In the first century BC Lucretius flipped the story into one of progress, imagining people fighting first with hands, nails and teeth, then with stones and branches, then copper, and finally iron. He guessed that metal was first smelted by accident in forest fires.
In 1565 Konrad Gessner published the thunderstone explanation, and the stones became known as ceraunia. Michele Mercati, superintendent of the Vatican's botanical garden in the late 16th century, studied them closely, noticed that the flints had been shaped by striking with another stone, and spotted the notch where a handle would fit. Vatican collections held New World implements of the very same shapes. Mercati concluded that people had used stone before they knew metallurgy, but his manuscript appeared only in 1717, long after his death. In 1734 the French antiquarian Nicholas Mahudel set out three successive uses of stone, bronze and iron, and generously credited Mercati with the idea.
The decisive step came between 1816 and 1825, when Christian Jürgensen Thomsen sorted the collection of the museum in Copenhagen that became the National Museum of Denmark. By grouping objects into types and matching them with excavation reports, he showed that tool styles changed over time alongside the dominance of stone, bronze or iron. By the 1830s he and colleagues such as J. J. A. Worsaae had freed the scheme from biblical dating, relying on typology and stratigraphy instead.
Refinements followed: John Lubbock split the Stone Age into Palaeolithic and Neolithic in 1865, and some add a Copper Age. The framework still orders prehistory in Europe, the Mediterranean and the Near East, but it fits sub-Saharan Africa, much of Asia and the Americas poorly; archaeologists in the Americas use a five-period system.
Source: Three-age system
