Here's why:
* -ulis is a common Lithuanian patronymic suffix, indicating "son of."
* Vali is a Lithuanian word that can mean "ruler" or "leader."
Therefore, Valiulis likely means "son of Vali," which could be a reference to a historical ancestor who held a position of power or authority.
It's important to note that surname origins can be complex, and there may be variations in the spelling or interpretation of the name over time. If you are interested in tracing your family history, it is always best to consult with a genealogist or expert in Lithuanian genealogy.