I have been trying to convert a stubborn Sunni county to Catholicism for 37 years.
(If it matters: All adjacent counties are Catholic. My chaplains over the period have been Catholics with between 20 and 23 Learning. My chaplains over the years have been set to "Convert Populace" and they are always stationed in the county in question. I am holding this county personally, as well as ten others that are all Catholic. I am Catholic and so are all my vassals. Everyone who holds land in the county is Catholic, except the adolescent son of a recently-appointed baron in a newly-built barony, who is Orthodox Christian.)
Is this just a streak of terrible luck (37 years...!!!) with the religious conversion, or is there anything else I can do to speed it up? Which of the factors I mentioned actually matter in the conversion? (Is it just the Learning stat of the chaplain that increases the conversion chance?)
Also, I noticed during this time that one of my vassals had a chaplain with all-zero stats who converted his county to Catholicism within a month of our conquest of it. (/jealous) Was this just lucky? Thanks for your help.