Go into the Stonecutter's Court then discover the Jewelry Store to the left of the guards that are speaking with each other, standing in the light. Go into the store, knock out the guard to the left of the entryway and then turn to the right. Discover the 3 cabinets below the red drapes. Use a lockpick on the center cabinet to obtain the very first mask. Turn around and slip into the cellar. Stay clear of the individual working at the desk while transferring to the rear left corner of the workshop. Interact with the painting and use the secret switch to unlatch it to discover a wall safe. Enter the code "739" to open the safe and gather the other item.