Something like that.
My Adoptive Mum had an entire wall of them back home, which were in fact acquired from upturned gravesites. The Cemetery (Which I was raised in) was so ancient, there were many unmarked graves. When they were uncovered (By myself and my two sisters, many times) we were to attempt to search for any sort of headstone, as to identify the occupant. We even got in touch with their families sometimes. From there, they could be reburied or cremated. The government recognized them as legal "property" of the land owner and everything just sort of went from there.
My collection of skulls, human or otherwise, has been reduced greatly since I moved away, due to not having the ability to retain them. Such is true for...most things I owned.
It's a cultural thing. We have a long history of such practice.
It was so prominent, that with the defeat of the Vikings, who in turn learned much from the Celts (and went as far as worshiping some of them as deities) and their settlement in France as "Normans" (Which means Norsemen) the custom continued, giving us the Catacombs I am sure you all know today. Equally impressive, though often forgotten in history are the monuments made by my Celtic ancestry, though much of our history remains forgotten by contemporary people, even in Europe. I have found that even in The United States, no one ever mentions the Irish Slave Trade in America, even though it was more severe, devastating and cruel than it's African counterpart. This is largely due to English historians, who did a very fine job of erasing everything that shines a poor light on their own culture.
