Oh dear! I'm sure a lot of us would like to get pages left to us like that bit in the Bible- so and so begat so and so begat so and so...
10 Generations seems like a lot to remember, even if you think of the possibility he might have known his great grandparent at most? Perhaps there was some record out there that he found. Perhaps a family Bible or something. Another possibility is that he might have made it up! I do recall a rootschatter saying years ago that they found an obituary for an ancestor's brother that said he was descended from some prominent family back in England- he certainly wasn't, so she said, but might have been a good yarn for him to tell and cash in from!
Any number of possibilities. But you'd think he would have passed it on
Small village in Yorkshire with a Viking name. And a traditional on of encouraging youngsters to marry within the village. Although my studies show that while this happened. Many cases of outsiders joining families and youngsters who didn't actually inherit property or leases leaving to live elsewhere
If the practice of withinbreeding was more prevalent going back in time. There's need to be some Local safeguards to steer youngsters away from marrying some one too close generically
Using imagination to go further. If the village did have a de facto expert on such matters. It quite probably been my ancestors mother. He is quoted as saying on his mothers side. Perhaps she knew the detail. And he only knew the broad facts. More likely people 'knew' these facts to enhance their claim to the property they inhabited, particularly if there was a possibility of dispute:
His mother lived 1827 to 1920 and only had one surviving child
My grandmother. Who I knew, would have known her
I never discussed genealogy with my grandmother. But it's notable that I could be just four generations from someone who still practiced the verbal tradition