What were Pythagoras' greatest achievements?

Pythagoras is best known for his contributions to mathematics, particularly the Pythagorean theorem, which establishes a fundamental relationship between the sides of a right triangle. He founded the Pythagorean school, which blended mathematics, philosophy, and spirituality, influencing the development of Western thought. Additionally, Pythagoras made significant advancements in the study of numbers, including concepts of numerical relationships and the idea that numbers have inherent properties and relationships. His work laid the groundwork for later mathematical theories and practices.