Complex sentence: Though named after the German chemist Justus Baron von Liebig he cannot be given credit for having invented it, because it was already in use for some time before him, but it is believed that the apparatus was made popular by him.
Split into simpler sentences: Though named after the German chemist Justus Baron von Liebig, he cannot be given credit for having invented it because it was already in use for some time before him. However, it is believed that the apparatus was made popular by him.