I'll have something after today, maybe this evening. As of writing, I am thinking of making the driving force behind this anti-Justinian movement might well be similar in character to the protestant reformation, with offers of greater autonomy for smaller principalities chafing under an imperial rule under the guise of a theological argument. 

More conspiratorial, of course. I don't necessarily intend to be guiding that conspiracy, but I want to set it up and play a character within it. I feel like this would be the best way to break off nobles that are 'locked in' under the Imperium's current ruling structure, as well as merchants and other key backers of a potential revolt.

Assuming that this is in line with the GM vision, of course. I am just brainstorming that side of things.