Why and how did that belief become so widespread?

The widespread belief likely emerged due to a combination of cultural, social, and psychological factors. Social reinforcement plays a key role, as individuals often adopt beliefs that are prevalent within their communities or societies, leading to a bandwagon effect. Additionally, emotional narratives and relatable experiences can make certain beliefs resonate more strongly with people, further solidifying their acceptance. Over time, these factors create a feedback loop, where the belief becomes entrenched and self-perpetuating through generations.