How did metal music originate?

I believe it was the group steppenwolf that coined the term “heavy metal thunder” in their song “born to be wild”

this can be argued to a point- but it is generally accepted that black sabbath are one of the grandfathers of metal, led zepplin may be one of the grandfathers as well.

sabbath decided to start playing music that was a bit on the “darker” side of things- they were coming out of the hippy era of peace and love- they grew up in a rough neighborhood in england and wanted to reflect some of that in their music. they chose dark themes- war , witchcraft, dark fantasy (fairies and superheroes) tony iommi playing his guitar in low tones and riffs, geezer doing the same on his bass, while ozzy adds his one of a kind voice to the haunting songs and bill ward just plays drums to it all, truly the first metal artists on the scene. the who kind of brought a bit of attitude to the mix with their smashing guitars and other equipment on stage. there were a few bands that helped create and inspire the metal we have today, and THANKFULLY SO!!!