You will find a leather cutter on the shelves on your left hand. THE BAKERY. Another door opens onto a room with a bread oven. Find then 2 pieces of bread, one in the oven, the other on the opposite table. Pour your green potion on one of them. You are now able to open the fourth door and meet an old templar. Throw your 'green bread' at him. Use then your leather cutter on the hospital statue to take a ruby. Repeat the operation on all hospital statues. Keep a watch for the 2 guards who are waiting for you outside the old templar cell.
Provided that you picked up the key the second guard left behind him after your fight, you can now open the mortuary door. In this room, push on the heart of the corpse and find his golden heart. Do not use it on the statue as long as you don't have in your possession 8 gems (among them 3 diamonds). Then use of the golden heart on the statue in the corner, quickly go towards the other statue at the other end of the room and drink out of the golden glass the statue offers you. You will become drunk and Wolfram will catch you and put you in jail.
Tied on the wheel, you can move towards left (right arrow on keyboard), to burn the rope which holds you. Once you are free, fight with the guard and do not forget to pick up your things on the table. To leave the room, invert the position of the 2 torches. This will open up a door for you. To avoid getting lost in the corridor, take the first to your left and show the ring without a stone to the old templar.
After he dies, pick up the objects he leaves behind and look in the chest. Take everything you find. Place the strange red stone inside the leather pouch to dazzle Wolfram. The 9 gems are ready for you to pick up in the golden chalice. To open the secret door, use your ring. Once you are back in the library, you may meet 2 devils dressed up in monks. In the library, you can open the big double door leading to the refectory.
Do not rush! You must first pick up the stack of plates on the table at your right handside and then walk towards the kitchen with the plates in you hands. Then go to the scullery where you will find two tombs. Use the stones on them and take the key which will allow you to open the door in the kitchen.