Why are many of Black Sabbath's classic hits slower in tempo than newer (late 70s on) metal songs?

[ChemicalWarfare84]

OK, so Black Sabbath is widely considered to be the first metal band. However, I've noticed that a lot of their classic hits are slower in tempo than later metal songs. Sure, songs such as "Iron Man" and "Sweet Leaf" have faster sections, and they did do fast songs such as "Paranoid", "Children of the Grave" and "Symptom of the Universe", but mainly, it seems like they did a bunch of slower metal songs. Why is this?

 

[Bloopy]

The short answer is because they're goddamn geniuses.

They wrote the song Black Sabbath to be deliberately scary (inspired by horror stories/movies, the occult etc.), and making it slow helped make it ominous and brooding. They knew they were onto something great and different, so they made it their direction, changed their band name to Black Sabbath and wrote more slow songs. Iommi's different style of playing due to his past injury may have been a factor too.

More generally, slow and heavy songs are great at conveying a negative/downbeat mood and they called it "downer rock" at first, which also applied to the heavier psychedelic rock bands at the time. Golden Earring - Everyday's Torture is a great slow song that predates Sabbath's releases:



Other bands like Deep Purple and Judas Priest brought the speed element to metal, which I guess became more popular in the late 70s as it gave the genre a point of distinction from the drugged-out hippies of the past. Thankfully we got doom metal too.

Awesome slow songs in blues weren't unheard of either, eg. Jimmy Witherspoon's version of Evenin'.

 

[Wyvern]

Because doom comes for us all.

 

[CiG]

Gustav Holst.