> It is thought that the ancient [Athenian democratic principle](hyperlink) of free speech may have emerged in the late 6th or early 5th century BC.
The hyperlinked page on democratic principle notably has no mention of free speech.
I've replied to a sibling commenter on Athenian "free speech" parallels - much of their association with modern concepts is appropriation.
> The right to freedom of expression has been recognised as a human right in the Universal Declaration of Human Rights and international human rights law by the United Nations. Many countries have constitutional law that protects free speech.
> The Declaration of the Rights of Man and of the Citizen, adopted during the French Revolution in 1789, specifically affirmed freedom of speech as an inalienable right.[7] Adopted in 1791, freedom of speech is a feature of the First Amendment to the United States Constitution
The idea predates the existence of the US.
https://en.wikipedia.org/wiki/Freedom_of_speech