Rafael Larco Hoyle found the first points in the 1940s, scattered across a stretch of sun-bleached ground called the Pampa de los Fósiles north of the modern town of Paiján. Larco was a cotton planter turned scholar, the son of a sugar baron, and he cataloged what he saw with the patience of someone who had grown up among the huacas of the Chicama Valley. Decades later the French archaeologist Claude Chauchat returned to the same pampas and mapped not dozens but a whole landscape of sites - camps where bands stopped for a night, workshops where knappers shaped preforms, quarries where they chose their stone. The picture that emerged was not of a tribe but of a way of moving: people who knew every water source and lithic outcrop in a country that looks, to a modern eye, like nothing but dust and distance.

The Paiján world was arid. Rodents and lizards and land snails, a few stubborn plants the old people learned to grind on stone, and not much else above ground. The sea, then retreated far to the west on a lower ocean, was the reliable larder. Those slender lanceolate points were designed for it. Mounted on reed shafts, they worked as harpoons for the fish that came in on the cold Humboldt Current - mackerel, drum, sea bass - and the long thin blades tell you something about what the hunters needed: length to pierce water and reach, strength enough not to snap on bone. Archaeologists have sorted the points into types with names like Talambo and Contracting Narrow Stem, each a small refinement on a design that worked. Early Paiján bands ranged far, camping between the coastal plain and the western slopes of the Andes as the seasons turned. Later groups stayed closer to home, which anthropologist Tom Dillehay reads as a sign that the climate had softened, wild plants and game had multiplied, and there was less reason to keep walking.

In 1975, working a site on the same Pampa de los Fósiles where Larco had started, Chauchat uncovered skeletal remains in a layer of ancient ash. A teenager of twelve or thirteen. A young woman of about twenty-five. Radiocarbon dates came back at 10,200 years before present, give or take a century and a half - the oldest human remains yet found in Peru. We do not know their names or how they died or what they believed about what came next. We know only that someone who loved them or feared them or simply outlived them laid the bodies down and covered them with ash, and the desert preserved what was left. The Paiján teenager and the young woman are the first Peruvians with faces, however stripped the bone has become, and everyone who came after - Chavín, Moche, Wari, Chimú, Inca - descends from the people who sent their dead into that ash.

Paiján belongs to what archaeologists call the Lithic Stage, the long stretch before pottery and villages and irrigation - before the Norte Chico pyramids rose at Caral, before the Chavín cult carried its stone jaguars up into the highlands. The Paiján did not yet build anything monumental. They left no walls, no plazas, no tombs stacked with gold. What they left were the tools and the trash of their living: broken points, bones of vizcachas, the shells of snails piled in lenses you can still see eroding out of hillsides. It does not sound like much. But the shape of a Peru-to-come is already there in the Paiján pattern - a people arranging themselves between ocean, valley, and mountain, learning which river runs when and which quebrada holds water after the rains. Everything the later civilizations built, they built on that first topographic knowledge.