The Exorcist

Na Hong-jin has cited The Exorcist among the films behind this one, and the last act is where it shows: a child who is not a child any more, a father who has run out of secular explanations, and a rite performed by somebody whose faith is not sufficient. What The Wailing adds is the question of WHICH faith, staging a Catholic deacon, a shaman and a stranger against each other so the audience never learns which one was right.

James Wan has cited the 1970s possession films as the register he wanted, and The Conjuring is built to be taken for one of them: period setting, unhurried camera, almost no gore, and specialists called in to a family home. The Exorcist established the shape the whole sub-genre still uses, a domestic crisis escalated to a rite, and the claim of a true case underneath it.