Try pick up the half empty bottle of meths next to Archie to trigger the required dialog topic with him. You need to find something he wants to trade for the meths. Search the waste bin near the guards at the main gate to find the half empty bottle of champagne. Take the champagne and talk to Archie about the meths, offering him the champagne as a trade. Take the meths and pour it into the waste bin. Now use the lighter to start a fire in the waste bin.
With the guards preoccupied in putting out the fire, enter the wafer factory through the side door.


Go through the double doors to the special wafer making room. While Nico talks to Sister Angelica, look around. After examining the monatomic gold at the base of the white mixer vats and the wafers on the conveyor belt, Nico and Sister Angelica return. Talk to Sister Angelica about the holy powder until Cardinal Gianelli enters the factory. Follow him to the monastery gardens.


You again need to find a way past the monks to get to the monastery door.

Once inside, go down the corridor to find that the door to Monsignor Devlin's office is partially open. Look inside, then enter the office. At the end of the cut scene you are given the manuscript book by Cardinal Gianelli.
Go back to the area where you entered the monastery and note the heavy beam has been removed from the trapdoor, so you can now open it.

Get Mark to partially open it (use his icon on the trapdoor) and while he does this, insert your golf club under the trapdoor to release the lock.

Go down through the trapdoor to a room with two large angel statues.
Do the angel statues look familiar? Have you examined the 'Ark of Ashdod' painting behind the desk in Cardinal Gianelli's office? As a point of interest, it's a replica of an actual painting done by Nicolas Poussin. Examine the bottom left and right corners of the painting's frame noting the position of the hourglasses and, in particular, where the sand in each hourglass is.



Both left hourglasses are vertical with the sand at the bottom. Both right hourglasses are horizontal with their sand on the right. You must replicate the settings on the hourglasses below the two angel statues.
First rotate the hourglasses on the LEFT angel to correspond with those on the frames, then slide the angel's head backwards and it should click into place. Repeat the process with the angel on the RIGHT, but the head won't click into place. Note that the slab on the floor opens, but it closes again. Get Mark to help by using his icon on the RIGHT angel's head.


You need to find a way through the door at the end of the corridor. Unscrew the junction box lid with the knife and then, using the rubber gloves, pull the wires apart. While holding the fire proof blanket remove the light bulb from the light socket next to the door and insert the C-4 explosives. You must now reconnect the wires in the junction box, again using the rubber gloves. KABOOM!
After the fairly lengthy cut scene go through the passage in the far left corner. Incidentally, you my want to check out the near right corner to find that Mark and Spallacci survived the skirmish.
You need to correctly rotate the three orange Celtic crosses on the wall to open a secret door. The manuscript book Cardinal Gianelli gave you provides a vital clue to solving this puzzle.

After going through the secret door you get to an area where you must negotiate George across the tiles on the floor. Again, the manuscript book contains clues to solving this puzzle. Take note of the five symbols in the centre of the manuscript, and what they represent.

Read the top part of the latin text for an explanation of the hierarchy between the symbols. Note that after reading the text it's also stored on the PDA.
The second, the battling armies ensure
Strict rules that they respect
No Mamluk can follow Templar or Hospitaller
Of lowly breed, Mamluk must follow Turk
To escape the Assassin, sidestep to right
Templar and Assassin must never follow the other
Always move forward and never back

From this text you know that there are five 'rules' that apply when moving from one tile to the next.

1)You cannot go to MAMLUK from either TEMPLAR or HOSPITALLER

From TURK you must go to MAMLUK


You can only move to the right from ASSASSIN

4)TEMPLAR and ASSASSIN cannot follow each other
5)You cannot move backwards
Before moving to a tile check that it complies with the 'rules'. There will always only one be possible tile that you can move to. For example, there are four tiles to select from at the beginning:

You cannot start at the TURK tile as it does not have a MAMLUK tile following it. (MAMLUK must follow TURK)
2)You can start at the HOSPITALLER tile, then move to the HOSPITALLER tile ahead of it.
You cannot start at the ASSASSIN tile as from there you can only move to the right, which is a TEMPLAR tile. (TEMPLAR and ASSASSIN cannot follow each other)
You cannot start at the TEMPLAR tile as there's a MAMLUK tile ahead to it. (You cannot go to MAMLUK from either TEMPLAR or HOSPITALLER)
You must therefore start off by stepping onto the HOSPITALLER (2) tile.

After crossing the narrow ledge, George falls into a pit and must get Anna Maria to pull the levers on the wall in the correct sequence. The same logic used to solve the floor tiles puzzle applies. There are four levers, MAMLUK, ASSASSIN, TURK and TEMPLAR. MAMLUK must follow TURK, so these levers should be pulled in that order. TEMPLAR and ASSASSIN cannot follow each other, so these levers cannot be pulled one after the other. Lastly, the MAMLUK lever cannot be pulled immediately after pulling the TEMPLAR lever. Therefore, the only possible sequence is:


You are then faced by yet another locked door. Examine the knight carved into the door to learn that it's Jacques de Molay, the Master. The next bit of latin text on the manuscript reads as follows:
The fourth, the Master shall show the way
Through the warmth of his heart
Apply a bit of lateral thinking to work out what can 'show the way' and how to 'warm his heart'.
A map 'shows the way', so put the map of Topkapi on the knight's heart, then use your lighter to set it on fire, thus 'warming his heart' and opening the door.
Next, you get locked in the room with poisonous gas. 

Examine the emblem on the brown base (where the ark must have been) to find it has a slot in it, and an inscription that reads: 'memento mori' - which is latin for 'remember you are mortal'. Have you seen this inscription somewhere else? Examine the rosary in your inventory to find the same inscription on it. Insert the rosary in the slot in the emblem to open another door.

You finally make it to the ceremonial hall, just in time to rescue Nico. Again use your trusty golf club to smash either of the cherubs on the ark, then after the cut scene, smash the other one.