Greyfriars Monastery

You wake with your head pounding.
As your eyes slowly adjust to the dim light you realise you are slumped in a church pew.
How did you get here?

4 Numbers are the key to this puzzle
Use the Magnifying Glass Controls to help you.

The walls of this place are so dusty. You should inspect them closely.
The key is also within the letter.

The Answer is: 1886

Checking the room there is a forumla on the wall.
Each of the Symbols is around the room.

Star = 2
Moon = 9
Skull = 10
Cup = 4

Plug them into the formula, and you have:

Star x Moon = 𝑥
(Moon x Skull) - Cup = 𝑥

2 x 9 = 18
(9 x 10) - 4 = 86