The descent from Tilmann Knepper shown on this site is not unchallenged. A surprising number of people, including myself, have found papers in their family documents showing descent from Hanspater Knepper of Austria, who immigrated in 1698. These all seem to be similar in content, leading one to believe they have a common source...be that the actual facts or someone's poor documentation of family history.
Unfortunately, of the fifteen or so versions I've seen from cousins far and wide, not a single one mentions the ultimate source of the information beyond family tradition. The earliest version of it I've found that has a date is Margaret Knepper's Genealogy of the Knepper Family in the United States (1906).
On the other hand, the Tilmann descent is generally well-documented. However, the difficulty with Tilmann — at least from my particular point of view — is that the critical link identifying the Godfrey Knepper in my family's documents and the Godfrey Knepper who was the son of Johann Gottfried & Maria Catherina (Frey) Knepper as the same person is only hearsay. So far, no one has been able to direct me to any primary source material that shows this to be true. So, while I believe that the Tilmann descent is more likely, I'm including this section.
The following is a transcription of one of the shorter of these family histories down to the Godfrey in question. In general, they agree that Hanspater was born in 1681 in Austria, and came over in 1698 from either Austria or Germany and settled "between the Schuylkill and Delaware Rivers." Some versions insert an "extra" Gottfried between the second John and the Godfrey mentioned in this account, but that would make six generations in 81 years, which is extremely unlikely and most do not portray it that way.
Fifty years ago a tradition was current among the older members of the Knepper family in Berlin, Pennsylvania, that the first Knepper to arrive in America was Hanspater Knepper. He was born in Austria in 1681 and with several members of his family came to North America in 1698, and settled in Eastern Pennsylvania between the Schuylkill and Delaware Rivers. He was a Quaker. He married and had four sons born to him as follows: Hanspater, Christian, Jacob, Abraham.
Abraham married and had three sons whose names were: John, Jacob and Hanspater.
John married and had three sons whose names were: Abraham, Jacob and John.
This younger John married and had three sons whose names were William, John and Godfrey.
William emigrated to Circlesville, Ohio; John settled in what is now Somerset county, Pennsylvania and Godfrey in what is now Cambria county, Pennsylvania.
These names certainly sound like the Knepper family but there are some issues. No Austrian Hanspater Knepper, or Johann Peter Knepper, has been established in the 17th century in America so far. Also, the Quakers were members of an English religious movement, not a German one. In fact, we know that many individuals with the Knepper surname were closely associated with the Church of the Brethren. While there are some surface similarities in matters of pacifism and dress — and in persecution in their home country — between the Religious Society of Friends (Quakers) and the Church of the Brethren, the latter was a German movement.