Finishing HW here what i can say about Ishgard.
I still believe the design of the kingdom is too much close of historical stuff, in my other topic i explained why.
But the reason of those choice can be something more of a political choice, to send a message, even if for myself i would prefer avoid so obvious reference to real history.
Isghard is a replica of the reign of catholic in western europe, with political and social structur we know from this time: power shared by Churche and Noble.
The time of the war with dragon 1000 year, match with the birth of Catholicism to the time where he is contested ; so around after the end of roman empire 450 , to 1450 1500 where the start of constation birth.
All the word belonging to Catholic building and organisation are in Ishgard, Archibishop is a pop elected in same way that the current pop in Roma.
12 knight of Thordan are the 12 knight of King Arthur which match up with the time where briton is converted to catholicism, and old ritual and faith are chased and forbidden.
The way how monotheism hold power in Ishgard is the same that Catholic did. Catholic forbidden to people to read and learn, kept the ancient knowledge of greek text,(philosophy, science, politic) to avoid any contest of its power. As we know all, rebirth of Europe is based on the rediscover of the ancient Text, thanks to the trade with the Arabian and muslim countries who took this legacy and worked on it. (that why they were in advance on science compared to catholic contries)
Isghard faith is build on a lie to justify its power and reason of existance, as Catholic did, saying to people they had to suffer their whole life to reach the paradise and forgive the SIn of the past (fruit of knowledge)
Fanatism : Ishgard show too way of fanatism, as the first crusade was a kind of bunch of people fanatic who wanted to free the Holy city.
Dragon : dragon are the symbol of all ancient faith and ritual which existed in europe befor catholic choose to destroy them, and forbidd them. They are also the root of wisdom that people of europe could have keep, a memory to the tradition, and a way for those people to find back their lost identity.