The first person to propose a heliocentric model of the solar system, where the Sun is at the center, was Aristarchus of Samos. He lived in ancient Greece around 310-230 BC.

While his ideas were not widely accepted at the time and were largely overshadowed by the geocentric model of Ptolemy, which placed the Earth at the center, Aristarchus is considered the first person to put forward the heliocentric theory.