Ancient Greece in the 19th Century

The great 19th century thinkers invoked the spirit of the Ancient Greeks just as the Greeks themselves invoked the muses. Cf Williams _Shadow of the Antichrist_ 30-33, also Butler _The Tyrrany of Greece over Germany_. What's the rhetorical effect of this invocation; how does it relate to the critique of Christianity and the rise of atheism in c19? How does this reflect a larger battle within that century between Ancient Greece and Christianity, Dionysus against the Crucified?