In the early spring of 1750, Philip LeMarchand set out for Toledo, Spain seeking to avoid the authorities of France.  There, he was given refuge among an ancient brotherhood who housed a secret library that had been compiled by the Grand Inquisitor, Torquemada.

Without much prodding, the head of the sect was able to convince LeMarchand to teach some of his techniques to the artisans of the order.  Much encouraged by the knowledge gleaned from the forbidden texts, LeMarchand was then commissioned to produce four constructs for the mysterious library.
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The first box, "The Mason's Keystone," was said to contain within it's designs several mathematical formulas that could solve any structural anomalies.

He handed the box over to an eagerly awaiting young draftsman who required aid for a building project.  LeMarchand smiled musing, "I give to you a simple tool, not an answer.  Go now and solve it's mysteries.  All you have to do is understand the question."

One day had passed, and the young man had not emerged from his chamber.  On the following day, he stormed into LeMarchand's workshop ranting about the calculations on the box.

"Monsieur, is this a joke?  Nothing measures the same twice!  I keep repeating the same patterns, but they constantly change by the tiniest fractions.  All my hard work is for naught.  How am I to finish my work when I have to keep starting over half way through?"

LeMarchand calmed the young man, telling him it was simply a matter of seeing it through to the end… no matter what.  "You do want to finish don't you?  Maybe I have made a mistake in giving someone so young and impatient a tool such as this."

Ashamed, the young man apologized to his senior craftsman for doubting him or his work.  He vowed to retire to his drafting table to rework his calculations.
 
 

The young man had locked himself in his room and worked feverishly for days.
Never stopping for food or sleep, even when his calculations were flawed and not of his own accord.  At the end of the fifth day, a new understanding had taken hold of him.  Voices and giggling could be heard from inside his chamber.

At the end of a weeks time, the head of the order visited LeMarchand in his workshop.  Admittedly concerned about the young man and his sudden solitude, he sought out the cause of his disappearance.  It was decided that the time had come to see what fruits the young man had borne from the device the toy maker had entrusted to him.
 
 

Upon opening his door, a strange scent of vanilla and charcoal was heavy in the air.  The young man was nowhere to be seen.  Every square inch of the man's room was filled with sketches, designs, drafts, patterns, layouts, and all manner of creations.

All were written in blood.  Too much for just one man.

"The Mason's Keystone" was found atop the student's drafting table.  A scroll tied with a braid of hair and a small sack lay beside it.  The scroll, also written in blood, read:
 

Philip LeMarchand opened the sack to find Antonio's eyes.

He smiled, put them back, and handed the sack over to the Grand Padrone. "Such visions…they do have their prices."  To which Santino Raphael De Torma, Grand Padrone to the order of St. Salamanca De La Necros Negro Biblious, last living descendant of Torquemada replied, "When will you have the next box finished?"

"I will need more supplies."
 

LeMarchand had killed six young prostitutes in
the construction of the Mason’s Keystone.

Antonio Sangristo was estimated in killing
twelve during his weeks tenure.

Ambrosio, or The Monk is a Gothic novel 

by Matthew Gregory Lewis, published in 1796.