Q re genealogy chart I inherited

SIL?

In fact it usually is the opposite of you are saying. It is most of the time easy to get back the first 200 years and maybe 400-500 years. Earlier than that it gets hard to find reliable sources that are written in the time the persons lived, and we have to rely much on secondary sources which are not that trustworthy as primary sources, which is written at the time of the event.

For most Europeans, the farthest back you could realistically go is about the 12th C., and that would require a lot of luck. For the average Euro-American, anything before the 15th C. gets shakier -- in fact, the majority of hobbyist genealogists in America never even get back to Europe with primary sources. For a very small number of royal families, you can get back to about 450 C.E., but the lines are debated.

The farther back you go, the more you enter what's usually considered to be the "mythological tree." This is the tree from the era where you don't have primary sources and instead must rely on myth cycles, poetic sagas, and other documents that are usually a blend of fiction and fact, heaviest on the former.

The genealogical mission of the LDS Church has actually cautioned its members against even bothering with ancestors prior to 1500 C.E. You can see their statement on this at https://familysearch.org/blog/en/family-tree-adam-eve/

So the simple answer is: No, it's not true, and your sister- or son-in-law shouldn't believe everything s/he reads on FamilySearch. :)

Thanks for the insight, and link.

We are related to nobility so I'm quite confident going back to when my grandfather's last name was first used. Who knows from there?

Something you'll see through your experience on Geni is that everyone with European roots is related to nobility, and unfortunately, a lot of American noble pedigrees are inaccurate. It was highly fashionable in the late 1800s for Americans to find their most recent "noble" ancestor, even if it meant fudging the data. Surname books in particular are often pretty flawed, though sometimes they're the only sources available for some people.

So I would just encourage you to make sure that you're using primary sources and not published genealogies in order to track down noble roots. As I said, every Euro-American has noble heritage -- it's a simple consequence of mathematics and the number of ancestors we have -- but you just want to make sure that you have the best information possible.