>>>>>In "Dubious Doings At Dismal Downs", we can see the dates of birth and death of Sir Swamphole McDuck (1161-1221), while, according to "Il Rinascimento Disneyano" and "Birth And Death Dates Of The Ducks, Coots And McDucks", you say the dates are, in your opinion 1190 and 1260... why?
I'm home from my fishing trip. But as I reread this question, I see I didn't need to check anything. Assuming that answering would require me checking some Barks story, I read the question carelessly. Rereading it, I realized there IS no such story as "Dubious Doings at Dismal Downs"! So I Googled that title, and I see it's "only" one of Barks' oil paintings. I say "only" because, while I'm happy the Old Master was given the opportunity to make some money off his popularity in his later years, I have never cared much for his paintings, so I was not familiar with this painting or the dates showing on the tombstone. I note that there is also another McDuck relative shown on another tombstone, a relative I did not have in my Duck Family Tree. I wonder why you didn't also consider that an "error"?
Barks' paintings were done for a *totally* different reason than his stories. The stories were intended to entertain comics fans by, as it turns out, the millions. The paintings were done to sell to a few wealthy investors, many of whom never knew who Barks was but were seeking a collectible investment in buying the original painting or the lithograph copies. As I say, I'm glad Mr. Barks profited, but I don't especially care for the entire idea. The paintings are not accurate scenes from his actual stories -- for example, this "Dubious Doings at Dismal Downs" scene does not occur in the story, nor does the scene in that "Return to Plain Awful" painting that I was commissioned to create a story to explain. And that instance proves my point...
Another Rainbow / Bruce Hamilton was the company that commissioned Barks to create those paintings to sell and produce as lithographs. They had done one beased on "Only a Poor Old Man" titled "Disaster at Money Lake" or somethng which showed the dam bursting and the money washing away. Since most buyers were NOT Barks fans and had never read his comics, Another Rainbow had complaints (and lost sales) because buyers did not understand what the scene represented! So, when Barks painted "Return to Plain Awful", I was hired to create a story to explain what was going on, otherwise buyers would not have a clue as to what was the deal with square chickens! My comic was included with lithograph purchases. (They could not send buyers a reprint of the original "Lost in the Andes" story since $crooge was not in tht story but *was* in the painting.)
Furthermore, there are contradictions to Barks' own stories in the paintings, such as showing the coins in his Bin being all GOLD which was never the case in the original American comics. It spoils the entire joke of the Bin being full of ordinary pocket change rather than valuable gold coins. I know European stories have always shown the Bin filled with gold coins, but I consider that a very sad error. The coins in the paintings were colored gold to please potential buyers unfamiliar with the original stories... gold looked prettier in the lithographs. But I will not believe that the Bin is filled with gold based on those later oil paintings which I know were never intended to be absolutely accurate to the original comics.
STILL -- If I had known that Barks had given Swamphole's dates in that painting, I probably would have used those dates. Why not? And I'm amazed that they are as close as they are to the dates I had pencilled into my rough notes on the Family Tree. Quite a coincidence!
But it all boils down to this: the dates given in that Italian book were taken from my private notes, NOT from anything ever intended to be published. I did not even know those dates were in that book -- I can't read it, y'know! So... this can't be considered an error.