In Assassin's Creed Valhalla, you may come across Rigsogur Fragments, which are a type of collectibles in the game. On this page of the guide, you will learn where to find the collectible and how to reach it. This will make it easier for you to max out the Sciropescire region.
The fourth page of the saga can be found in Quartford.
It is in the building, right by the window. You will get inside by jumping through a hole in the wall. Then turn left and you will see a fragment of the saga.