Is there any other way to raise Preist Peity?

gday, another rookie question......

I want to stack the college of cardinals like many of you kind folk have suggested in other threads.

My question is, aside from killing heretics, is there any other way to raise a preists piety?

Killing heretics is definitely the fastest way, but sending them way out into the boonies (places with 0% Catholicism) is a bit more consistent in the long run. A good way to stack the College is to just churn out priests and as soon as they're ready, just send them towards Arabia, Russia, and Northern Africa. Crank out Churches in your interior cities where you don't need military buildings, and then you can get a few Theologians Guilds which will start your priests with some decent piety.

Looking at the data files the general theory is that for the "Faith" traits, the % of your religion needs to change by a large amount (8%) and your priests must have recently arrived in the province (<3 turns). For the higher levels it is 10% and 5 turns. You get Missionary and Heresy bonuses from recently converted provinces that have >95% your religion, i can't make sense of the details. Anyway the common strategy is the "God Squad", build as many priests as you can (at least 5) and send them in one big group along with your cardinal(s) to lands with low (0-30%) Catholic. Concentrate on one region at a time until it is >95% before moving on to the next. Your priests will gain piety very quickly, especially if there are a few heretics for them to denounce. Your cardinal(s) will also gain piety, and move to the top of the ballot for pope.