WHYYY? I mean, is this some sort of sneaky attempt to curb SA influence by making it look like Terran is an SA-friendly nation? Why'd be just suddenly (right before I joined, no less) decide to go Bloodstars on us? :-P
SA is one of Terran's state religions. Well, heh, technically, one of our privileged institutions, alongside Triunism and the Moot. Yes, Sanguis Astroism and the Véinsørmoot have the same legal status in Terran. So yeah, Terran
is an SA friendly nation. SA's history in Terran goes back even further than Triunism's history; Terran was originally founded as by SA members fleeing Caerwyn.
There was some RP involved.
Ultimately, there was quite a bit of RP involved; just not all of it public.
Also, SA is more fun.
And I'm sure politics played a small part as well.
But these are the main reasons. Triunism was boring as hell but, most importantly, it didn't satisfy any of Hireshmont's spiritual desires, nor, conveniently, any of his temporal desires for Terran to be a diplomatically important state. Combine spiritual dissatisfaction with temporal ambition, and a rival institution which can satisfy both... and you've got a conversion!
