Our modern thinking is also constrained by similar misjudgments, we just like to think we're smarter than that. 500 years hence, people will laugh at our idiocy.
Which single-handedly started a space race which led to colonizing the moon (and, uh, mostly exterminating the indigenous population which was totally different than the folks who were supposed to be there in the first place).
Oh, except it was also a completely different moon that we somehow weren’t aware was there.
Nothing he was proposing should have worked, and yet somehow not only did it, but it made everyone (who funded it) fabulously rich beyond their wildest imaginings.
Idiot savant?
In fact, probably all of us do this.
Truth really is stranger than fiction.
Idiot was a strong word. But not as brief.
So, it seems at some points he made claims he had a route to the orient and later he referred to it as 'West Indies'. Perhaps he knew the truth all along but had reasons to mislead.