Who put forward the golden section? How did it come into being?

The golden section was put forward by Pythagoras.

It is said that in ancient Greece, Pythagoras was walking in the street one day. Before he passed the blacksmith's shop, he heard the blacksmith strike the iron, so he stopped to listen. He found that the blacksmith had a regular rhythm in striking iron, and the proportion of this sound was expressed mathematically by Pythagoras.

The golden section was first recorded in the 6th century BC, and the origin of the golden section ratio is mostly considered to come from Pythagoras School. In the 4th century BC, eudoxus, an ancient Greek mathematician, first studied this problem systematically and established the theory of proportion. Around 300 BC, Euclid absorbed eudoxus's research results and further discussed the golden section systematically. His Geometry Elements became the earliest treatise on the golden section.