Assassin’s Creed Valhalla Sancta Helena Church Ability or Book of Knowledge is also a bit trickier to get, just like the Oxeneforda Ability. The Ability counts as an Essexe Wealth collectible and allows you to unlock the Harpoon Impalement Ability upgrade.
This Book of Knowledge, though, is inside the Sancta Helena’s Church Tower, and as you can guess, it requires a key. The good thing is that by finding the said key, you’ll be able to get two collectibles because next to the ability upgrade, you’ll also find the Essexe Hoard Treasure Map.
On the map below, you can see that this Ability is found in the northern corner of Colcestre. You can also notice that Eivor, in my case, is standing in the upper right corner of the main building, which is the said church.
When you get to this location, inside the church, you’ll find a locked door, and this door leads to the tower, but the only way to get inside is by finding a specific key.
Where To Find the AC Valhalla Sancta Helena Church Key
The first step here is to exit the church in question and go around it. What you are looking for is a shelf you can move because the shelf in question masks the entrance to a hidden room. So basically, go around the church until you see the shelf in my screenshot below.
Behind it, as you can see, is a window you can smash. Easy right? So, enter the room, and here you’ll find two items. The first is a Note of Hatred on the stone coffin, and the second is the Sancta Helena Church Key on the chair behind the said coffin.
With the key in hand, return to the door inside the church and unlock it. Now look up, and you should see a ladder. At this point, you should be inside a round chamber. Behind you is another shelf you can move, and you should pull it until it is right under the ladder; otherwise, you won’t be able to reach it. Make sure it is in the position you can see below.
Next, climb the ladder, and when you reach the first floor, look up again to spot another one. Shoot the locker on the ladder (pictured) to pull it down.
Then head up, and here you will see the Book of Knowledge on a wooden table. Next to it is the Essexe Treasure Map and the Wicked Man’s Diary, which you may want to read.