I've read that both Tony Iommi and Geezer Butler enjoyed classical music and were influenced by those composers. I think you can hear it here. Every Sabbath member is an exellent musician. Bill Ward is highly regarded among drummers, Iommi a guitar genius, and Butler known for a unique, hard driving bass style.
I would even venture that only a British guitarist could have done what Iommi accomplished. I believe his particular influences and musical instincts allowed him to create this sound. My reasoning, no American guitarist sounds like this. JMHO