It's difficult to pinpoint one specific person as the first to believe the Sun doesn't move across the sky. The idea of a heliocentric model (Sun-centered) developed gradually over centuries, with contributions from many thinkers.

Here's a breakdown of how the idea evolved:

* Early Greek Philosophers: Some, like Aristarchus of Samos (c. 310–230 BC), proposed a heliocentric model. However, their ideas were not widely accepted due to the prevailing geocentric (Earth-centered) view.

* The Geocentric Model: The dominant view throughout antiquity was the geocentric model, championed by philosophers like Aristotle and later by Ptolemy in his Almagest. This model explained the apparent movement of the Sun, Moon, and stars around Earth.

* Medieval and Renaissance: The heliocentric model resurfaced during the Renaissance. Nicolaus Copernicus (1473-1543) presented his own heliocentric model in his book "De Revolutionibus Orbium Coelestium" (On the Revolutions of the Heavenly Spheres). His work was groundbreaking but initially met with resistance from the Church.

* Galileo Galilei: Galileo's observations with a telescope in the early 17th century provided crucial evidence supporting Copernicus's model. He observed the phases of Venus, which were only possible if Venus orbited the Sun.

Therefore, it's more accurate to say that the belief in a heliocentric model emerged gradually, with multiple individuals contributing to its development. Aristarchus can be considered a pioneer, while Copernicus's work is widely recognized as a major turning point.