From ancient times, Azpen had been heavily influenced by the voice of religion. Because of this, relations with the theocratic city-state recognized as a holy city nation were good, and they could receive their aid. However, conversely, they had to tread carefully around the temple, making it hard to do anything freely.
But to say the holy nation was the only problem? That wasn't true either. If there were only one holy nation, the King of Azpen could have simply been a bit more cautious here and there while still pursuing his own will.
In other words, religion alone was not the issue. Looking back through history, the Duchy of Azpen was a nation that began from the rank of Duke. It was a land established with the Empire's permission.
Examining it more closely, one would have to view it as the Empire's scheme successfully binding a peerless hero to the earth. But such is the judgment of hindsight after years have passed. To those who lived in that era, Duke Azpen would have been nothing short of a hero among heroes.