http://agathe.gr/democracy/the_athenian_army.html
The Athenian Army From the very beginning, the Athenians were compelled to fight for their new democracy. Their dramatic victories over the Boiotians and Chalkidians in 506 B.C. led many to attribute Athenian ... Recovered from a well in the northwest corner of the Agora, this lead strip carries an inscription recording the registration of a horse. On one side is the name of the owner, Konon; on the other a description of the horse, a chestnut, with a centaur brand, as well as its price, 700 drachmas. ... At the end of the year these records would become obsolete and could be reused or discarded, as in the case of this example found in a well.