The encyclopedist of Greek geometry — and its last great voice. Pappus of Alexandria (fl. 4th century CE) gathered, commented on, and extended centuries of mathematical work in his Collection, preserving key insights from Euclid, Archimedes, Apollonius, and more. His theorems are sharp, his problems challenging, and his style rich with geometric imagination. He didn’t invent the wheel, but he catalogued the parts — and left enough tools behind to keep future mathematicians busy for centuries.