Certainly the (Catholic) Church had a lot of temporal power, especially in the Papal States, but sovereignty was a bigger thing than in Imperial China or Muslim conquests or caliphs.
Huff also cites the legal framework (amongst other factors): the independence of the judiciary (even from the Church, even though clergy sometimes acted as judges) and a focus on a documented due process acted as checks on runaway power.
The Medieval Origins of the Legal Profession by Brundage is also an interesting read:
* https://en.wikipedia.org/wiki/Render_unto_Caesar
Certainly the (Catholic) Church had a lot of temporal power, especially in the Papal States, but sovereignty was a bigger thing than in Imperial China or Muslim conquests or caliphs.
Huff also cites the legal framework (amongst other factors): the independence of the judiciary (even from the Church, even though clergy sometimes acted as judges) and a focus on a documented due process acted as checks on runaway power.
The Medieval Origins of the Legal Profession by Brundage is also an interesting read:
* https://www.press.uchicago.edu/ucp/books/book/chicago/M/bo56...
It even covers Roman law, and how it managed to be salvaged (to an extent) and be used as a base for European law, especially starting in the 1200s.