The Samadrian Heresy is the name given to the sorcery practiced by some cults in Samadria. In addition to the rites and cult practices common to the worship of the Twelve in all of the six kingdoms, some cults in Samadria also accept the patronage of certain potent otherworldly beings, who teach a powerful - but dangerous - sorcery. In the Western Isles, this practice is forbidden, and sorcerors who practice the Samadrian heresy are hunted down and killed if they will not recant. They are especially hated by members of the so-called "Church Militant" - a political faction within the Western Church that has always agitated for more power for the church, but which over the last two centuries has risen to prominence through the fight against the Samadrian heresy
No-one knows exactly when the so-called Samadrian Heresy started. In its practices, it bears some relationship to the city religion of Paddish, and it may be that it started when the Samadrians first expanded into the Harrowlands. However, the first clear demonstration of the sorcerors from the heresy was shown in the second war with Ostragya, where sorcerously-summoned creatures played a major role - showing that the heresy was well-established before this expansion. It also shares similarities with the sorcery of Tyranc, so some people think it was bought by refugees from the wars of Lumulea.The cult started to spread to Ostragya in the wake of that war, but it was vigorously resisted and was declared a heresy. Practitioners of the heresy claim that this is a purely political move, motivated by jealousy of their peerless sorcery and that the beings they summon are avatars of the Gods. Their opponents charge that these beings are demons and point to the corruption that inevitably follows in their wake.
Not every cult on Samadria has a "patron" as they call the beings that they worship, but many do and the association of heresy and sorcery with Samadrian cults is becoming strong in the west. This is resented by those Samadrians (still the majority) who do not practice the heresy and combined with national feeling has weakened the ties of religion between Samadria and the other 5 kingdoms. Although the Arcobulon is still the nominal head of the whole church, his influence has waned in Samadria. Finally, there are some people who have turned away from the Twelve completely and worship Patrons directly in small cults. Although this is officially not a crime in Samadria - the church has never had a history of schism or religious intolerance - the church militant will kill such people if it can find them and the heresy is starting to breed distrust and even conflict among Samadrian cults.