This is in the Monastery of St. Catherine. Let's make sure I am looking at the right thing.
Before we get to this part, the walkthrough says (this is in the library):
Go to the bookcase. Look at open chest on the extreme left of the bookcase. Pick up magnetized rosary and read the letter of Proclos to Simon.
Does that sound like where you are?
If so, I can provide another sentence of information about the puzzle if needed.