When Gerald tells the story, he says that it happened "eighty years ago, back in the Middle Ages", and in the next scene as it is continued, motorized cars and clothing from the early 20th century can be clearly seen, which never existed in the Middle Ages. Since Gerald said the murders the Ghost Bride committed, her suicide and the events prior were eighty years ago, then it actually happened in the 1910s rather than the Middle Ages.
It could actually be possible that Gerald was joking about the story taking place in the Middle Ages when it took place much sooner than that, or he considered the early 20th century like the Middle Ages.
When Arnold says, "It'll only take him about a half an hour to figure out that the door only locks from the inside", his pants change from their normal blue color to Arnold's skin color.
