It's possible depending on how far back in time the Legion's conquest of the viking Lands is.
The warden's campaign begins in the south of the legions lands, which is as far away from the northern viking lands as it gets. That holden cross is there, dealing with business that is not connected to fighting of vikings, proofs that there is no longer a direct connection between the lawbringers and gouverning/bringing law to viking lands. It could still be the origin of their order, we cannot know that yet (or maybe never will, depending on how deep the story will be)