Honestly I find early Pantheons are the norm on long game speeds. Someone inevitably finds a Faith ruin, or, more likely, everybody in the world except me inevitably finds a Faith ruin. x.x
The Celts and Ethiopia are pretty much guaranteed to get the Faith machine rolling earliest, what with passive Faith generation from turn 1 and that Monument that gives 2 Faith. Thankfully their start biases dissuade them sniping that sweet, sweet Desert Folklore/Dance of the Aurora, but then the sheer number of Pantheons that get started and push back me acquiring my own makes me tempted to turn off Ancient Ruins entirely. Gratefully now BNW makes Piety available from the start and +2 faith from each half-cost Shrine sounds delicious.