Assassin’s Creed Valhalla introduces the "Hidden Ones Bureau", where Hytham tasks Eivor with hunting down six codex pages.
These documents reveal more about the Hidden Ones, and can sometimes require a little bit of lateral thinking to find.
Each is accompanied by a piece of Assassin's gear, too, so there are more tangible benefits for seeking them out.
There are also no waypoints, so we've put together this handy guide.
Assassin's Creed Valhalla Codex Pages: All Bureau Locations
The first one is nice and easy to find, and you'll find it to the east of Ledecestre's central town.
Look for a map marker for "Wealth–Armour" and you should find the Assassin's sigil on the floor.
Send your raven to spot a bag of stones (we've no idea why anyone would be hanging stones so precariously) and shoot it with your arrow.
This will break open the floor, so you can hop in and grab the Codex Page.
From the amphitheatre in Lunden (not a typo), head northeast to find a hole in the ground.
Use the columns to jump in, pull Eivor out of the water, and aim your bow at an area where your reticule turns red.
From here, swim through the opening before climbing up and shooting the red barrels.
Look through the door and you'll find another Codex Page.
Temple of Ceres Bureau
Southwest of Glowcestrescire (try saying that ten times fast), you'll find a temple with two statues outside.
Slip under the door (break a post to create room), and then use your torch to clear poison in the rooms ahead.
Smash a door with an oil barrel, and then open the chest for another Codex Page.
Venta Belgarum Bureau
Head to Witan Hall in Wincestre, find a hole and drop down into the water below.
Move the blockade inside, then throw an oil barrel at a breakable door on the other side.
You can then grab the Codex Page.
If you head to Jorvik, find the theatre and speak to a girl nearby talking about goats.
She'll lead you to an area, and you can then jump into a trapdoor within the cemetery.
Follow the path until you find a room with boxes hanging above, then look for a grate that leads to a ladder.
Head up the ladder, through a door, and unlock the Codex Page with a key on the bookcase.
This one is found in my home county of Essexe, and you'll want to seek out Coclestre (stop sniggering).
At the Ealdorman's house, look for a tree to climb up and over, revealing a breakable pit – you'll need to use an oil barrel to smash it.
Inside, climb the platforms and look for a block that can be moved, then head through a room until you see a banner that Eivor can climb on the right.
Jump across to another banner, and then into a pool.
You'll find a key underneath the surface. Open the door, then you can shoot the block through a grate.
After that, head back to the climbable banner, then to the now unlocked door for a Codex Page. Phew.