A quorum is the minimum number of members of a deliberative assembly necessary to conduct the business of that group. I have written a little about the ancient Athenian quorum before, but before I get to that, let me explain the Athenian government body really quick--or at least the parts relevant to this post. There is a longer summary to be found here, but as that is a Pagan Blog Project post as well, I am just going to assume you have read it. So, short summary:
Back in Classical ancient Athens, if you were adult male Athenian citizens who had completed their military training as ephebes, you were required to partake in the democratic assembly of citizens, called the ekklesia. It consisted of about 25,000 voting citizens. The ekklesia, in turn, was managed by the boule of 500 citizens, taken from the ranks of the ekklesia. The boule, finally, was managed by 50 members of the boule, called the prytaneis. Everyone in the ekklesia voted, but their votes were tallied by the boule-members of their tribe, who related the votes to the prytanis of their tribe, who then tallied and proclaimed the votes. Previous to the Classical age, smaller assemblies would dispense judgment, or the judgment was dispensed by the king.
Perhaps the most well-known example of voting in ancient Athens comes from Aeschylus' Eumenides where Orestes faces divine judgment after slaying his mother in revenge for the death of His father. Athena presides over this judgment, and Apollon speaks for Orestes, but the vote is in the hands of the Athenian people, although Athena has the winning vote in case of a tie.
"O men of Athens, ye who first do judge the law of bloodshed, hear me now ordain. Here to all time for Aegeus' Attic host shall stand this council-court of judges sworn, here the tribunal, set on Ares' Hill where camped of old the tented Amazons, what time in hate of Theseus they assailed Athens, and set against her citadel a counterwork of new sky-pointing towers, and there to Ares held their sacrifice, where now the rock hath name, even Ares' Hill. And hence shall Reverence and her kinsman Fear pass to each free man's heart, by day and night enjoining, Thou shalt do no unjust thing, so long as law stands as it stood of old unmarred by civic change. Look you, the spring is pure; but foul it once with influx vile and muddy clay, and none can drink thereof. Therefore, O citizens, I bid ye bow in awe to this command, Let no man live, uncurbed by law nor curbed by tyranny; nor banish ye the monarchy of Awe beyond the walls; untouched by fear divine, no man doth justice in the world of men. Therefore in purity and holy dread stand and revere; so shall ye have and hold a saving bulwark of the state and land, such as no man hath ever elsewhere known, nor in far Scythia, nor in Pelops' realm. Thus I ordain it now, a council-court pure and unsullied by the lust of gain, sacred and swift to vengeance, wakeful ever to champion men who sleep, the country's guard. Thus have I spoken, thus to mine own clan commended it for ever. Ye who judge, arise, take each his vote, mete out the right, your oath revering. Lo, my word is said."
In the Eumenides, twelve judges then come on stage and cast their vote in one of two urns--one to vote Orestes guilty, the other to vote him not guilty. The results are tallied and Orestes is cleared of blood guilt.
Voting in Classical Athens would have been much the same. Prior to the changes to the political landscape of Athens in the sixth century BC and onwards, made by Solon and Kleisthénês, it appears votes were more often settled by talking or shouting during assemblies. As this was of voting was decidedly personal, those of higher birth or greater power would have been able to sway votes. Solon, especially, worked hard to abolish these influences in decision making. The far more neutral voting system of 'bind' votes, where votes were cast in urn or other holders was considered far preferable.
Votes were tallied in a few different ways: one was to use stones of varying colors, and ascribe one color to 'yes' votes, and the second color to 'no' votes. All lots were case into a single urn, which was cracked open after everyone had voted, and tallied. The second option was the one portrayed in Eumenides: two urns, one type lot. A third option was a particular one; it was only used when deciding who would be ostracized. When a person was ostracized, potsherds (ostraka, ὄστρακα) with names scratched on them were used as lots, and he who received the most votes, was ostracized for ten years.
During an ostracism (ostrakismos, ὀστρακισμός) each member of the ekklesia would choose a politician they wished to have 'ostracized', or exiled for ten years. If any one name received a majority and a total of 6,000 or more votes, that man would have to leave Athens. The picture up top features some excavated ostraka naming prominent politicians still well-known to historians today: at the top, Aristeides, son of Lysimachus on the left, and Themistokles, of the deme Phrearios on the right. At the bottom, Kimon, son of Miltiades on the left, and Perikles, son of Xanthippos on the right. Ostracism was often used preemptivel, as a way of neutralizing someone thought to be a threat to the state or potential tyrant. As such, ostracism had no relation to the processes of justice; there was no charge or defense, and the exile was not in fact a penalty; it was simply a command from the Athenian people that one of their number be gone for ten years.
For a small category of votes a quorum of 6000 men was required, and ostracisms were included in that number. Another was the granting of citizenship to métoikos, if they had done something important for the city of Athens. These decisions were considered too important to leave up to smaller numbers.
The Athenian direct democracy we are now unfamiliar with besides when judging rounds of Top Model or Idols, allowed every (adult male) citizen the exact same vote, and equalized the political landscape. Quorum votes were especially important, as the decision was not only backed up by 6000 men, but they had voted on it together, bringing these men--and the city of Athens--closer.