Two qualifications need to be put on that label, however. In the first place, the intellectual advancement of Athens did not start with Pericles, but was in full bloom one hundred years before him. This suggests that a sense of freedom and the support of free thought were in place during the time of the tyrants.
Secondly, the reign of Pericles signals the beginning of the end for Athens. After the Persian War, it became more imperialistic and sought to extend its power around the Aegean. That eventually caused a confrontation with Sparta setting up the Peloponnesian War and the defeat of the Athenians. Sadly, the “Golden Age” was both the pinnacle and the beginning of the end for Athens. Greed and the desire for power had corrupted once again.