How were Athenian citizens divided into four property classes under Solon?

To address the economic and social unrest in 6th-century BCE Athens, Solon instituted a timocratic system that replaced birth-based privilege with political rights determined by wealth. He conducted a census of annual income, measured primarily in agricultural products like grain, oil, and wine, and divided the citizenry into four distinct classes:12

• Pentakosiomedimnoi: The "five-hundred-bushel men," representing the wealthiest class.2
• Hippeis: The cavalry class, consisting of those who could afford to maintain a horse.2
• Zeugitai: The hoplite class, or those who could afford the armor of a heavy infantryman.2
• Thetes: The poorest class, who were admitted to the Ecclesia (the general Assembly) under Solon’s reforms.12

These divisions determined political eligibility: while all citizens could attend the Assembly, higher governmental offices were reserved for the top two classes, and all but the thetes could serve on the Council of Four Hundred. By tying political responsibility to these economic statuses, Solon laid the foundations for the future democracy of Athens.13