Before the coming of the Platonics, Rome was governed by a Senate and Popular Assembly. This was due to the overthrow of King Tarquinius Superbus in 509 BC. Unlike the Confederation, Rome was highly patriarchal, with it being rumoured that women were even forbidden to drink wine or vote, given no official political status and not being allowed to join the army, use a sling or ride. The city was also aggressive toward other Italian nations such as the Samnites, Oscans an importantly the Greeks of Magna Graecia. Regarded as the second greatest western threat (the first was Carthage), plans had been in place to take it ever since the times of the Diadochi. In 275 BC, the Epiran philarchon Pyhrra conquered Rome. Although the legions of Rome, with their flexible tactics and troop types proved effective, they did not stand up to the female (and male) cavalry archers led by the philarchon herself despite being on hilly territory combined with classic phalanxes and the psychologically dangerous elephants. Rome was condemned for its misogyny and Roman women are encouraged to break all the exclusive social taboos put on them. A new Kallipolis was set up, under the control of Epirus until it was felt that Rome was safely assimilated.
As a puppet of Epirus, Rome was forced to take part in all its wars and accept whoever the Epirans installed as leaders. One of the great Epiran-Roman expeditions was the conquest of Carthage. For over 100 years, the Carthaginians had been a cause of hassle and conflict, the most obvious example being the incursion of Hannibal from 264-241 BC. By 146 BC, the Romans were able to invade Africa itself long enough to lay siege to Carthage. They got Epiran support when they explained that Carthage had attacked Numidia, which was a Roman ally. so the city was besieged, taken and then something terrible happened. The Roman leader, Scipio Aemlianus orders his troops on a massacre, with Carthage to be destroyed, most of the population killed and survivors have their tongues ripped out so the Punic language dies. The Confederation had wanted the city to be absorbed like Rome, as it wouldn't require repopulating the province. It was also judged that Scipio had allowed spirit and desire to take over reason, wishing Carthage destroyed because Cato the Elder had brought it up in every speech, so was unsuitable for the post of philarchon. He was deposed and sent into retirement. This was relieved a decade later when he was permitted to campaign against Celtiberians. The Epirans appointed Tiberius and Gauis Gracchus as joint philarchons, as both were as good as each other. Their first act was to start a poor relief campaign using money from the rich (any objections was met with the gladius). Another factor in Scipio's demise was his purchase of a massive amount of salt to plow into the ruins of Carthage to symbolise permanent destruction, which was a waste of salt and pushed up the price dramatically.
The Third Punic War had demonstrated that the Romans were capable of military conquest, and eventually were able to break off from Epirus. Their appointment of the Gracchi was the last official act of Epirus as puppet master. From now on, Rome was an independent Kallipolis (within the Confederation), and when the Chinese war began, Rome was able to spare enough legionnaires to be a visible contributor to the Platonic cause. It also led a campaign against Celtiberians in 133 BC to incorporate the Iberian peninsula into the Confederation (and expand its own territory).
In 14 BC the son of controversial politician Gauis Julius Ceaser, who led a civil war in the 50's BC became the philarchon of Rome, His power doesn't really increase, unlike in the OTL where he becomes the first Emperor. However his father was highly dictatorial in this timeline and was too close to the Egyptian leader Cleopatra VIII, resulting in his assassination. This means little but he and many others were shocked when the Parthian philarchon Vovones was deposed in an illegal coup. Octavian took him in while the Macedonians and Palmyrans worked with loyal Parthians to correct this injustice. He also recommended a demanding census of the troubled state of Judea just to prove the Confederation could do what it liked to them.
Julia the Elder and her husband Tiberius were in charge until 44. In 33, they and many others were surprised by news from Judea. It was reported that an immigrant Galilean Jewish reform preacher named Jesus had attacked the Temple of Jerusalem, driving out the money changers and swindlers who contaminated the house of the Jewish God. Many philarchons welcomed Jesus, believing he would be a great help in assimilating the troublesome Judeans providing he doesn't undermine the Guardian/Civilian balance. He doesn't.
In 98, the philarchon Marcia Ulpia Nerva Traianus, known to most Romans as Trajan, began a campaign of conquest amongst the north of Europe. Many tribes have been influenced by Platonic principles, such as the Iceni, Silurians, Belgae and Arverni, but the Dacians have been mostly left alone. However they hadn't left the Confederation alone and as the Chinese war drained manpower, the Dacians were able to launch a series of raids. Trajan took several specially equipped legions and eliminated Dacia as a threat. The spoils of war enabled the construction in Rome of a new Forum, Market and memorial Column depicting action in the campaign. Trajan selected Vibius Julianus as Ceaser (the Roman philarchon was known as Augustus) and then moved into China through Hsiung-Nu territory. Recruiting several tribes by promising them a good fight and lots of booty, Trajan was disappointed that the Confederation forces present wanted to make peace. The Hsiung-nu had to be satisfied, and Trajan even threatened to fight battles and lay sieges peace deal or not as promises had to be kept. The Platonic Chinese convinced the Romans that reason demands the centuries long war ends, so the Hsiung-nu were bought off. A few tried to fight but were beaten back. The compensation also included a war game between the Hsiung-nu and Confederation cavalry archers using (supposedly) non lethal arrows. The negotiations took place over 2 years from 108-110, as much had to be discussed. The Chinese get the North of Eurasia while the Confederation get's the South. Africa is to be decided when the time comes along with any newly discovered lands should any be found. Meanwhile, the Romans take Britain and Gaul- they claim that they're not north enough to be Chinese territory and besides, if nobody tells the Chinese, they won't care.
Rome was traditionally pagan, with a pantheon similar to that of the Greeks, with some gods like Apollo being interchangeable. In 313, the philarchon Constantine converted to Christianity, a religion based on the teachings of the preacher Jesus. This did weaken the Kallipolis slightly as the top officials are now more concerned about the afterlife than the present. He did set up a new city on the site of Byzantium known as Nova Roma (later Constantinople) which unintentionally became the new site of a Roman Kallipolis in just over a century.
The fall of the Roman Kallipolis
The raid on Rome.
In 410, the Gothic leader Alaric attacked Rome itself. He had worked for it in the past, but now, seeking a home for his people to set up their own Kallipolis and outraged at how they had been treated- like dirt, unequal filth no better than primates. The Guardian Class is strengthened and 3 sieges take place, each more effective than the last.As a Christian, Alaric doesn't want to break the faith of a key city, so restricts looting as much as possible. However, no foreign army had been in Rome since the Epiran invasion, so this struck a massive blow to morale and many saw it as the beginning of the end of Rome as a great power.
With the state under siege, it wasn't long before Rome lost power to someone else. The Goth leader Odoacer attacked in 476, believing Rome no longer served the greater good. Although it had lost much material value, it was symbolically the last member of the Confederation to oppose a new war with China. The Hsiung-Nu were destroyed by the Eastern Kallipoli when reasoned consideration demanded genocide, unlike 6 centuries before with Carthage. However, it takes until 532 for the Confederation to act. Odoacer was also looking to set up a utopia for his people, so with northern Italy under his control, he set up a capital at Ravenna. The last vestige of power was that Rome was now the base of the new Platonic Christianity in western Europe.
The Kallipolis of Rome was restarted in 1000 and existed as one of many Italian city states, others including Milan, Florence (later part of Rome), Naples (later part of Sicily) and Venice. It played a key role in the battle against the Reform Union in the 16th century, though that resulted in the RU, along with some British mercenaries launching an attack on it. Like the other Italian city states, Rome was solely Civilian, with the Guardians operating in mobile bands with leaders known as Condottieri. They enforced the spirit aspect of society and fought other Kallipoli for a price. Condottieri bands were trustworthy as long as they received compensation and didn't get a better deal somewhere else.