Assassin’s Creed Valhalla Diodurum Ruins Roman Excavation counts as one of the Melunois Mysteries you’ll need to complete in the first area featured in the Siege of Paris DLC released by Ubisoft.
The AC Valhalla Diodurum Ruins Roman Excavation we’ll cover in the guide below; allows you to collect the Diodurum Key, which you’ll use to open the door to the Hidden Ones’ Bureau in Paris.
So, let’s see how to finish the Diodurum Ruins Roman Excavation in Assassin’s Creed Valhalla Siege of Paris DLC.
Where To Find The AC Valhalla Diodurum Ruins Roman Excavation
The AC Valhalla Diodurum Ruins Roman Excavation Mystery it’s in the same place as the Diodurum Ruins Fast Travel point you’ll need to synchronize.
As you can see on my map, you can find it in the northern section of Melunois, just north of Chartres Church Ambush Mystery.
How To Complete The Diodurum Ruins Roman Excavation Mystery
As said, in order to finish this Mystery, your goal is to find and collect the Diodurum Key, which happens to be in the same room where you can find the Golden Flame Ability or the Book of Knowledge detailed here.
So basically, if you reach the location of the Ability, you’ll also find the Key.
This means that you’ll use the same method to get inside, and you’ll start by performing a Leap of Faith in the pond under the High Point. After you synchronize it, obviously.
Next, you’ll need to dive and follow the underwater tunnel, which leads to a dead-end.
From there, you’ll swim up, and you’ll enter a new tunnel where you’ll see the Hidden Ones’ logo on a stone door.
Interact with it, and in the next room, you’ll see a gap filled with water. Jump, then swim right, following a new underwater tunnel.
You’ll need to take two left turns to reach a new dead-end and then swim up into a room with a breakable wall like the one in my screenshot.
Here, turn around to spot a red jar you can throw to destroy the wall.
Behind the wall above, you’ll find the room where the Wealth is waiting for you.
Once inside, turn right, and you’ll spot the table below, as well as the Diodurum Key on it.
After getting the key, the Melunois Roman Excavation ends; however you’ll notice that you’ll start a new quest.
How To Use Diodurum Key
If this is your first key, then you should know that you won’t be able to use it right away because you’ll need the other two.
Basically, the Diodurum Key, along with the one from Amienois, and the one from Evresin, allow you to enter the Assassin Bureau in Paris, which is your objective for the Hidden main quest.
Until then, though, your next goal is to exit the ruins, which is extremely easy through the door on the left. If you encounter difficulties, simply follow the same path as the one outlined at the end of the Diodurum Ruins Ability guide here.