Thank you PetitBourgeois for the nomination, and thank you all for the support! I have noticed that writing an AAR of my game has really improved the fun, and seeing people liking it is one of the greatest things ever!
I know, phargle. The problem I had, was that due to westernization (twice!) my my innovation/narrowmind slider was at -5. I was at minus Much missionaries per year

. It took me quite some time to get that slider back, and get the right national idea that gave me an extra +0,5 missionaries/year. At the start of the 16th century, I was gaining 0,05 missionaires/year... But now,
finally, I'm having 0,75 missionaries/year

. That NI and some movement in the slider gave me a real boost. So expect more Islam in the next update!