Dual Cities

The Dual Cities, officially the Dual Cities of Eye Bay and John's, refer to the union of Eye Bay City and John's City which was formed in 15 YT. Rumors of the Dual Cities joining the Great Harmony sparked the Kindmountian-Harmonic War, but this was not officialized until 4283 HE (134 YT), in the middle of the war.
The Dual Cities utilized a dominance system between its two constituent cities. The Choosing Assembly, a randomly chosen assembly, decided at any time which of the cities was dominant and which was subservient. The dominant city had full control over external affairs, but each city otherwise largely autonomous from one another.

Geography

The Dual Cities were located at the southern tips of Great-Eye Lake (OTL Lake Wānaka) and John Lake (OTL Hawea). The land they occupied was mostly flat and arable, making them an important agricultural and animal husbandry nation in the region, yet still overshadowed by the Great Harmony in that domain. Due to their position on the coast of major lakes, fishing was also a major source of food for the country.
Their border with the Harmony is generally recognized to be along the Great River, but some accounts push the border back about a kilometer.

History

As independent cities

Not much is known about John's City and Eye Bay City as independent cities. They were probably founded near -60 YT as independent coastal cities and traded with the rest of the Great River large cities. They stayed independent during the trend of large cities forming clans or tribes and both expanded southwards. The two cities had an amicable relationship and were close, although their politics differed considerably.

Founding of the Dual Cities

After the Moa Clan Integration War, during which the Harmony forcefully annexed the dissenting Moa Clan, the cities of John's and Eye Bay feared that they were next, as they too had refused to join the Harmony. While the latter did not have the strength to continue their aggressive expansion, out of security the two independent cities joined as one in 15 YT, becoming the Dual Cities of Eye Bay and John's, and creating a unique dominance system as a solution to who would control external affairs.

Integration into the Harmony

Politics

As an independent nation

City politics

Each city had its own way of governing itself, and internal affairs did not significantly change when the Dual Cities were formed.
In Eye Bay City
Eye Bay City had a very similar form of internal governance to Kindmount and was very much influenced by the strong nation, partially explaining their historic preference for Kindmount. Caste-estates would impose taxes on their subservient caste-estates, but were regulated by a council of representatives from each caste, chosen by their respective caste-estates. This council oversaw the economy by regulating, and sometimes lifting or imposing, taxes. Unlike Kindmount's Casteless Council, the council was not declared casteless, nor were its constituents determined by a series of challenges, nor was it elected for life.
The education and security of of Eye Bay City citizens were assured by the warrior-priest caste-estate, and similarly other caste-estates managed their own part of city life to some extent. The central tax-collecting government oversaw all city management and had significant influence. Additionally, a strong rivalry existed between castes, like in Kindmount.
In John's City
John's City did not elect a council to oversee the caste-estates or the economy: rather each caste-estate had a specific role to play in the governance and management of the city, and were almost fully independent from one another, having near-full control over their specific domain.
A central government existed to collect taxes from people based on their caste, but caste-estates did not tax each other. This made John's City politically much closer to the Harmony than to Kindmount, perhaps explaining its historical preference towards the former.

External affairs

The Choosing Assembly was an assembly comprising 8 members from each caste-estate. These members were randomly chosen within their castes.
The Assembly's sole purpose was to decide which city was dominant. If one representative called for a vote on changing the dominant city, then it would be debated and then executed. This resulted in at least one vote being called each time the Choosing Assembly convened, which was once every two days, and sometimes sooner in case of an emergency.
The dominant city's central government acted unilaterally on matters concerning external affairs, notably foreign policy, white city matters were left to each city. Thus, which city was dominant was vital in determining how it would behave and interact with other nations in the region, as the two cities were often opposed in matters of foreign policy.

Within the Harmony