How did Athenian democracy differ from most modern democratic systems?

By the version of their democracy

Explanation:

Athenians used direct democracy, which is people gathered and voted on the spot. We today use representative democracy that is a group elects others to go and speak for them and make decisions for the group of people.

Athenian democracy differ from most modern democratic systems mainly by the citizenship rights.

Explanation:

Athenian democracy developed around Sixth century BC in the Athenian city of Greeks. Athenian form of democracy was completely unique from the modern democratic system because it granted the citizenship rights to only men those who owned property and who completed the military training.

They formed around thirty percentage of population in Athens. It refuses to give the citizenship rights to women, slaves and children. But we cant deny that Athenian democracy is the foundation of many modern democratic system.