It did take both circumstances and leadership. Without the semi-mythical leadership of Mathurin, the religion could easily have fractured. Mathurin doesn't say much, so when he does say something, people pay attention. And it's obvious that he is paying attention, and not just ignoring everything. He comments in ways that get people thinking, and moving in the appropriate direction, without obvious pushes and orders. It is a very deft touch, and highly effective.