who first said the earth was round

The idea that the Earth is round dates back to ancient Greek thinkers. The earliest known proposal that the Earth was spherical is attributed to Pythagoras around 500 B.C., largely on philosophical and aesthetic grounds. Aristotle (384–322 B.C.) provided some of the earliest physical evidence for a spherical Earth, such as observing the curved shadow of Earth on the Moon during lunar eclipses and the way ships disappear hull-first over the horizon. However, it was the Greek mathematician Eratosthenes in the 3rd century B.C. who first proved the Earth was round by calculating its circumference with remarkable accuracy through observations and geometric reasoning. Eratosthenes is credited as the first person to scientifically measure and confirm the spherical shape of the Earth. So, Pythagoras was likely the first to propose a round Earth, Aristotle was among the first to provide physical evidence, and Eratosthenes was the first to prove it with measurement.