Complex sentence: One of the most widespread areas of this underworld was ruled over by Hades, a brother of Zeus, and was known as Hades (originally called'the place of Hades').
Split into simpler sentences: One of the most widespread areas of the underworld was known as Hades. This was ruled over by a god, a brother of Zeus, who was called Hades (his realm was originally called'the place of Hades').