The Bishop's realms all stopped being theirs when they died, even if their followers still inhabit the land and worship their memory. So I don't see why Yngya would be the exception to that.
The area now* called Ewefall was her's, but it didn't start that way. It was someone else's before her arrival, and it was inevitable to become someone else's after her arrival. The place literally does not exist on the map in Pilgrim.
They've mentioned before that Anchordeep, Darkwood, Anura, and Silk Cradle were not always called that. There is a finite amount of space on their island. Names and places change by the nature of the lands and what they're used for. Everyone is living in the ruins of the era that came before them. And no one has any more right to the land than anyone else.
Because they are all native to this island.
With the only exception being the pilgrims, who are clearly marked and distinguished from everyone else.
*it doesn't even seem to actually be called that in the "present day" because no one calls it by name. Everyone besides the lambs just call it "the mountain". Not even Mystic Seller calls it by "Ewefall".
We're told time and time again that Gods literally change the landscape to suit their needs, and that can only be via supernatural means. There were. Hundreds. Of Gods. And yet only 4 regions are identified (along with 4 points of interest within those regions) on the map. Woolhaven and Ewefall not being recognized locations multiple generations after their disappearance isn't something unique to the lambs. It's, in fact, a natural occurrence in this setting. How many times have they said that it's the nature of beasts to forget?
When your "culture" is centered around the fact that you're all in the same cult, then yeah, your customs aren't going to persist when your cult is gone. In the context of this setting, that would literally heresy. Adopting the practices and beliefs of a God that isn't your own. And that is how the culture of the lambs functions, because The Lamb doesn't know anything about it despite there being lambs that lived outside of Yngya's shadow.
It's Yngya's culture. Because it's Yngya's cult. It became synonymous with "lamb culture" because it's all they would've known for thousands of years. Multiple generations.
