In the late 6th century B.C., the Greek city-state of Athens began to lay the foundations for a new kind of political system. This demokratia, as it became known, was a direct democracy that gave political power to free male Athenian citizens rather than a ruling aristocratic class or dictator, which had largely been the norm in Athens for several hundred years before.

Athens’ demokratia, which lasted until 322 B.C., is one of the earliest known examples of democracy; and although recent scholarship has complicated the Eurocentric view that it was the first democracy, this ancient political system was extremely influential in the Mediterranean region. It inspired similar political systems in other Greek city-states and influenced the ancient Roman Republic.

The last tyrannos, or tyrant, to rule Athens was Hippias, who fled the city when Sparta invaded in 510 B.C. Two or three years later, an Athenian aristocrat named Cleisthenes helped introduce democratic reforms. Over the next several decades, subsequent reforms expanded this political system while also narrowing the definition of who counted as an Athenian citizen.

What was Cleisthenes’ motivation for initiating these changes? Unfortunately, “we don’t have any good contemporary historical Athenian sources that tell us what’s going on,” says Paul Cartledge, a classics professor at the University of Cambridge. After the 514 B.C. assassination of Hippias’ brother, Cleisthenes may have sensed there was growing public support for a system in which the city-state was not governed by an elite ruling class.

“Cleisthenes, I think probably partly for his own personal self-promotion, put himself forward as champion of the majority view, which was that we must have some form of popular, ‘people’ regime,” Cartledge says.

To participate in the demokratia, a person had to be free, male and Athenian. In the beginning of the democratic period, Athenian men had to have an Athenian father and a free mother. By the mid-5th century B.C., Athens changed the law so that only men with Athenian fathers and mothers could claim citizenship. Because there were no birth certificates (or DNA tests) to prove parentage, a young Athenian man’s political life began when his father introduced him at their local demos, or political unit, by swearing that he was his father and bringing witnesses to attest to this, Cartledge says.

The Athenian democracy was direct, rather than representative, meaning that Athenian men themselves made up the Assembly. Because there were no population censuses, we don’t know exactly how many Athenian men there were in the 5th century B.C., but historians have commonly estimated the number to be around 30,000. Of those, around 5,000 might regularly attend Assembly meetings. In addition, Athenian men served on juries and were annually selected by lot to serve on the Council of 500.

There were other government positions that were in theory open to all Athenian men, although wealth and location played a large role in whether a man could take on a full-time government job or even make it to the Assembly to vote in the first place. Still, there were some positions that were only open to elites: the treasurers were always wealthy (ostensibly because wealthy men knew how to handle finances), and the 10 generals who occupied the top government office were always elite, well-known men.

And then, of course, there were all the other people in Athens who were completely cut off from political participation.

Assuming that there were about 30,000 Athenian men when the city-state developed its democracy, historians estimate there were probably about 90,000 other people living in Athens. A sizable portion of these people would have been non-Athenians who were enslaved (by law, Athenians couldn’t enslave other Athenians). Others were “resident aliens” who were free and lived in Athens but didn’t meet the requirements for Athenian citizenship. The rest were Athenian women and children, both of whom couldn’t join the Assembly.

Although these groups never gained the same political rights as Athenian men, there was some debate about whether they should be able to, says Josiah Ober, a classics professor at Stanford University.

“We know that the question of ‘could women be political beings?’ was debated,” he says. In 391 B.C., the Greek playwright Aristophanes wrote a comedy, Assemblywomen, in which women take over Athens’ government. “It’s meant to be funny in some ways, but there’s a serious thought behind it,” he says. Although Aristotle thought women weren’t psychologically fit for politics, Ober notes that Aristotle’s teacher, Plato, wrote in The Republic (circa 375 B.C.) that an ideal political system would include both women and men.

In addition, “there were moves several times in Athenian crisis history to…free large numbers of slaves to make them citizens, or at least make them resident aliens, on the argument that [Athens] needed more people who were full participants in the war effort,” Ober says. However, “these tended to get defeated.”

Athens’ democratic period also coincided with the city-state’s tightening of its control over what was originally a voluntary alliance of Greek city-states, but had now become an Athenian empire. The city-states had their own governments, some of which were influenced by Athens’ democratic system, but didn’t have any political power in Athens’ demokratia.

Athens’ democracy officially ended in 322 B.C., when Macedonia imposed an oligarchic government on Athens after defeating the city-state in battle. One of the Athenian democracy’s major legacies was its influence on the Roman Republic, which lasted until 27 B.C. The Roman Republic took the idea of direct democracy and amended it to create a representative democracy—a form of government that Europeans and European colonists became interested in several centuries later.