So I finished the birth of tragedy and it was pretty interesting, although he's already beginning to sound unhinged, and I reject the central theory (that music represents our internal will and is therefore superior to the plastic arts of drawing and sculpture, which always represent the phenomenal world. My q there would be, what about surrealist or abstract art? Although perhaps a bit unfair cos it came later.
He also has this interesting insight about foundational myths... he says that Semitic and Aryan (meaning Greek/Roman) founding myths are very similar, in that they both basically involve Gods as generally benevolent, but also as rule-setting. And the key kick off for any kind of story/drama is that the humans transgress in some way, go beyond what God has proscribed for them.
So the classic examples are the fall of Adam and Eve from the Garden of Evil, and in the Aryan world, Oedipus' solving of the Sphinx's riddle, or Prometheus' stealing of fire.
So this is interesting enough, but Nietzsche also says that there is a key difference between the Semitic/Aryan stories. In the Semitic world, the transgression is coded feminine, involving deception. Whereas the Aryan version codes the transgression as active/brave, masculine.
So even here, you can see how it's but a hop, skip and jump for him to infer Christianity as "weak" etc...