4. Was Beethoven of noble birth?

No, he was not, unless those above-mentioned dissident researchers are right. But this is not very likely. In principle the prefix "van" in Dutch and Flemish only points to a particular place, not to noble birth, in contrast to the German "von". Seen from a Dutch point of view the composer's name was not just "Beethoven", but "Van Beethoven", the word "van" being a part of the name itself, not pointing to a particular descent. There is a slight difference between the Dutch and Flemish way to write down Beethoven's name. The Dutch way: Ludwig van Beethoven or Van Beethoven. The Flemish way: Ludwig Van Beethoven of Van Beethoven. Beethoven without ''van'' is German.