The Καλλίπολη Συνομοσπονδία (Kallipolic Confederation) is the main grouping of nations that follow the society laid down in Plato's Republic. This has lasted since the time of the Diadochi to the present day, but has lost most of its meaning by 2014, becoming merely a catch all term.
Originating in 336 BC, this empire was founded by Alexander the Great, who while seeking to eliminate the Persian threat was also influenced by Aristotle's new interpretation of Platonism. Upon Alexander's death, the empire was divided among the Diadochi as nobody knew who to give the philarchonship (philosopher king) to as the only instruction was "to the strongest." Members included Egypt, Selucia, Pergamon,Bactria, Macedon and Greece. Later members include the Epirans, some Indians, Scythians, some Chinese and Romans. Judea was also within the Confederation, though by how much is up for debate.
The general social structure is illustrated by the chariot. The driver is reason, one horse is spirit and the other desire. Both horses must be kept in check by the driver to ensure smooth running. Outside the illustration, spirit should also control desire. So overall, the rulers control the army and the people while the army controls the people. This has been seen by some as despotic and almost the opposite of utopia, but Plato believed that as only philosophers actually know where the ship of state is going, only they should lead it.
The Confederation has no central government and each member could be considered an individual sovereign state. This is because Republic was meant for a city state, not a large empire. This means that there are multiple philarchons, some of which are more powerful than others. For example, the Seleucid philarchon was more powerful than the Macedonian one. Members are also known to go to war, as briefly happened among the Diadochi. In fact this is very common and most Confederation wars are inter-Kallipoli. Philarchons of states might also have subordinate philarchons of cities and settlements that are tributary or vassal states- the 16th century British Kallipolis included a High King of Ireland in its government. A few are simply puppets- Rome was a puppet of Epirus until 146 BC where it became a member in its own right.
Philarchon- the society's reason
These are the philosopher kings of the various states.The philarchons are not generally treated as a separate class, but rather one who can command both to behave and keep them under control. These are not chosen democratically, instead they are chosen by merit, with approval from the democratically elected legislatures of the Guardian and Civilian classes. They are not allowed personal possessions, however anything they need is provided. In practice, this only happens in cultures that tolerate such harsh living, such as Sparta (Hellas). Many states allow their rulers to own property, some amassing a vast fortune, such as in Egypt. Even those that do keep to the letter of the philosophy tend to provide their rulers with grand clothes and houses, to symbolise authority. However these do not belong to the rulers and if deposed, they are impeached and removed from office, at which point these items return to the state.
Guardian- the society's spirit
These men and women (Plato was very clear about this) follow a strict code, even (officially) reproducing only on prescribed festivals, with all offspring having the entire participants as parents. This ensures that there is no incest. The Guardians are further subdivided into the actual Guardian class and the Auxiliaries. As the soldier class, members are not permitted personal possessions, similar to the philarchons, though in practice, many keep certain items such as loot or good luck charms. Guardians live in communal habitats similar to a military camp and undergo constant training for whatever they may be needed for, whether to control the Civilians or to embark on wars. The Auxiliaries are the main research and development personnel of the Kallipolis when it comes to science and technology that may be useful to war as well as a police force. Members of this class tend to be highly belligerent and violent, though accept that war is not always the first, only or best method for solving problems. Gender bias is relatively unknown, though racism is common, but only permitted (if at all) towards enemy troops.
Civilian- the society's desire
Labourers and workers, who are the rest of the population and the most numerous, though a balance between the 2 classes is usually maintained. These are the main agricultural, industrial, religious and scientific personnel, though focus on civil science and technology, such as robotics and energy production. They also form the bulk of diplomats. Members of this class tend to be highly proud and demanding, hence the need for their wishes to be refined for the good of society. Plato highlights 4 types of labourers, the shoemaker, the builder, the farmer and the weaver. There can be a gender bias in this class and is mostly similar to the OTL cultures own biases, but are often milder- there is no shame in having a female child anywhere for example and chivalry is near non-existent. Racism however can be worse.
For a start, with there being 2 classes, there may be one rule for the military and one for the people. Also absolute power corrupts. Not only are rulers obliged to lie to the people to keep them under control (on the pretence of keeping them happy) but may start to gather so much power they begin to disregard the rules and turn truly despotic. Philarchons may have massive power but this is to serve society, not themselves. If this happens, reason in compromised and spirit & desire win. For example, in 146 BC, Scipio Aemilianus the conqueror of Carthage was supposed to simply subdue the city and convert its inhabitants, but in frustration at Carthaginian wars throughout history and the urgings of Cato the Elder led Scipio to allow this desire for genocide take over and destroyed the city, sowing it with salt. Not only did this raise the price of salt, it also required the province of Africa to be rebuilt and resettled. Scipio was removed by the Epirus in it's last act as puppet master of Rome and replaced by the Gracchi brothers.
It is also likely the Civilian class may find itself oppressed by the philarchons and Guardian classes. In all cases of a solely civil and non military revolt, the Guardians have won. There should be just as many military personnel as non-combatants to balance society and the military is designed to be self-sufficient. Therefore, some fraction of Guardian support is needed for a revolt to succeed. One example is in France in the late 1790's. While the lower elements of both classes were being exploited and put into poverty, the rulers granted themselves a life of luxury. Both the Civilians and Guardians revolted and brought down the nobility. Declaring a true republic and making every position, even the philarchonship directly elected, they promoted the idea of liberty, equality and fraternity, declaring there to be Universal Rights of Man (apparently not covering the right not to be guillotined, drowned or shot after unfair trials, assuming there was a trial at all).
During the earlier ventures into industrialisation, questions were raised over slaves and their use. Few could imagine a world without slaves, but it was said that machines were now the new slaves. Humans were either freed on mass or kept in slavery as means of control. In Europe and North Africa, some freed slaves were exiled in order to control the population and allowed to settle in new Kallipoli to start their own societies. By the 19th century, there was a growing movement to stamp out the ownership of people entirely. By the present day owning, buying or selling slaves is illegal and carries the harshest punishments. Britain, Europe and West Africa are so sensitive about stamping out slavery that freedmen who object to their oppressors treatment or show any form of affection are deemed accomplices and punished with the owner. Even before then, taking a Guardian into slavery was punishable by something so horrible all record of the process it was erased from history in the 18th century. Slavery has always been a controversial issue and by the present is nearly over.
As the Confederation is not one county but many bound by a single belief, internecine wars occur just as often as in our world. Sometimes these may stop to confront a common outside foe such as Dacia, Carthage, Native Americans or the Chinese but some of the most violent episodes in Confederate history occurred when Platonics fought Platonics. A notable example is the 16th-17th century Reform Union. However, the Confederation has developed a culture of "brothers against cousins and cousins against strangers", so any attempt to attack a Kallipolis will likely result in even the targets arch-enemies helping it. This means that the KC is highly resilient and difficult to fight.
Many states keep their own cultures, they're just reworked to fit Aristotle's new interpretation of Republic. Post-Roman Germanic based nations such as France or Britain also incorporate a feudal system, while some states in the Indian subcontinent use a caste based system in conjunction with the main two classes. Art is considered of value only if it informs us of the world, so while heraldry and portraits are popular, pointless or useless items are not appreciated. Names are more difficult. For Civilians, it is the same as the OTL. For Guardians it is more complicated due to the deliberate state of unknown parentage. British Guardians use a regular forename and create a surname based on a intentionally designed serial code. Hence, Anne Boleyn is actually Anne B013YN, while Davy Jones might be Davy 70NE5.
See also Religion (Plato Succeeds)
Currency is used as a medium of exchange for Civilians while the Guardian class is not allowed to use money. Like culture and religion, individual Kallipoli have their own system. In Arabia, the Kharajite movement has introduced a form of communism which has been replicated. In the chaos following the destruction of the Roman Kallipolis, new states gathered organised feudal systems, which had been pioneered by the Parthians. Northern Italian city states and the Netherlands are prone to capitalism. The Guardian class tends to be poorer as a whole than the Civilians due to its need for equipment but individual members tend to be richer- as they're not allowed personal possessions, they can save up more (though not in money). Industrialisation began in the 11th century as political unity had been broadly achieved and the mathematics & resources were available.
This has been moved to Technology (Plato Succeeds). If you were directed here for a technological explanation, it is now in that article.