Is there any way to stop garrisons revolting?

[unmerged(3127)]

It's really irritating when you build a huge fortress and it revolts, takes the province over without any fight and then you have to spend years sieging it with 100+ armies. Is there any way to prevent it?
Can I also descrease the fortress level? Estonia revolts too often - I actually want its fortress to become minimal again.

 

[Tue]

As for the constant revolts - click on the province, click on the church, locate the revolt risk precentage and let your mouse pointer hover over it and you'll get an idea of why your province is revolting. When you conquer a province there's a 3% risk for the first 10 years, 2% for the next 10 and so forth. Also, your religious tolerance is important. If you have set your tolerance towards protestants to 0% and then conquer a protestant province the inhabitants won't be too happy about it.

Tue

 

[hjarg]

... and upgrading fortress actually lowers the chance that rebels will take it over. Not much though...

 

[unmerged(548)]

Is there any way to stop garrisons revolting?

Higher walls and lower revolt % helps to minimize the chance.
However there is always a chance to lose the fortress to revolters.

If Estonia revolts frequently (if you play Russia) I would take a peak at my tolerance towards christians too.