The Memoirs of Sherlock Holmes - The Musgrave Ritual
Watson tells Holmes to organize his papers. Holmes pulls out a box with "a crumpled piece of paper, an old fashioned brass key, a peg of wood with a ball of string attached to it, and three rusty old discs of metal."
It's from one of his earlier cases about the Musgrave Ritual. His college acquaintance, Reginald Musgrave, came to him with a case: His butler, Brunton, disappeared after being caught looking through family papers. Brunton asked for one week before leaving the job. But he disappeared a few days before the week was up.
Result: The Musgrave Ritual is an initiation for young men of the family to join the estate. It goes like so:
"Whose was it?"
"His who is gone/"
"Who shall have it?"
"He Who Will Come."
"Where was the sun?"
"Over the oak"
"Where was the shadow?"
"Under the elm/"
"How was it stepped?"
"North by ten and by ten, east by five and by five, south by two and by two, west by one and by one, and so under."
"What shall we give for it?"
"All that is ours."
"Why should we give it?"
"For the sake of the trust"
Holmes figured out that they were directions and it lead to a cellar. Brunton's dead body was in it.
Earlier, they had fished a bag of metals and stones out of the pond. It turned out to be the crown of Charles the Second.
Ancestor Sir Ralph Musgrave was the right hand man of Charles the Second. He was protecting the crown until the king could get it but died before then. He created the ritual as a way to remember the location.