How to get a quick prestige boost ?

[Valfary]

Playing as Brandenbourg, I got elected Emperor and expanded quite aggressively (700 dev in 1530).
However, I want to switch to protestant to form Prussia, but doing so I lose the imperial title and go back to duchy rank, massively exceeding my governing capacity, without enough prestige to upgrade to kingdom.

Do you have any idea on how to handle it ? I think I could use this thing to get the "grand duchy" achievement, but I'm afraid that it would kill this campaign.

[Stephano]

can you upgrade to kingdom in the hre? or if you are an elector you can?

Also just declare quick wars to annul treaties and remove rivals. that gives a bunch of prestige especially if there are a lot of small guys in there.

Another one is patronage of the arts burgers estate.

age bonus prestige per dev from missionary

[Valfary]

I think that the age bonus is the key, thanks for reminding me about this one. I guess I'll wait till I have enough splendor for it then.

[Malvastor]

You can get a big lump sum from humiliating a rival, I think.

[Medicles]

If you start as Brandenburg, you automatically become a kingdom when forming Prussia.