As we know Friedrich Nietzsche was not only a philosopher but also a classical philologist.The fact that he was the youngest to take the chair of classical philology of the university of Basel(24 years old) speaks on its own about Nietzsche's Intellectuality.
As a classical philologist Nietzsche had a big knowledge about Ancient Greece and this obvious because some of his philosophical works are dealing with the ancient Greeks and their inventions (like theatre for instance) from a philosophical perspective.
An interesting excerpt from Nietzsche's first work with the title "The birth of tragedy" shows how much esteemed were the ancient Greeks for him.
We read at the 15th unit of the book:
In the sense of this last mysterious question we must now state how the influence of Socrates has spread out over later worlds, right up to this moment and, indeed, into all future ages, like a shadow in the evening sun constantly growing larger, how that influence always makes necessary the re-creation of art—I mean art in its most profound and widest metaphysical sense—and through its own immortality guarantees the immortality of art.
Before we could recognize this fact, before we convincingly established the innermost dependence of every art on the Greeks, from Homer right up to Socrates, we had to treat these Greeks as the Athenians treated Socrates. Almost every era and cultural stage has at some point sought in an profoundly ill-tempered frame of mind to free itself of the Greeks, because in comparison with the Greeks, all their own achievements, apparently fully original and admired in all sincerity, suddenly appeared to lose their colour and life and shrivelled to unsuccessful copies, in fact, to caricatures. And so a heartfelt inner anger always keeps breaking out again against that arrogant little nation which dared to designate for all time everything that was not produced in its own country as “barbaric.” Who were those Greeks, people asked themselves, who, although they had achieved only an ephemeral historical glitter, only ridiculously restricted institutions, only an ambiguous competence in morality, who could even be identified with hateful vices, yet who had nevertheless laid a claim to a dignity and a pre-eminent place among peoples, appropriate to a genius among the masses? Unfortunately people were not lucky enough to find the cup of hemlock which could easily do away with such a being, for all the poisons which envy, slander, and inner rage created were insufficient to destroy that self-satisfied magnificence. Hence, confronted by the Greeks, people have been ashamed and afraid, unless an individual values the truth above everything else and dares to propose this truth: the notion that the Greeks, as the charioteers of our culture and every other one, hold the reins, but that almost always the wagon and horses are inferior material and do not match the glory of their drivers, who then consider it amusing to whip such a team into the abyss, over which they themselves jump with the leap of Achilles.
source:The birth of tragedy by Friedrich Nietzsche