In 1907, the French chemist Georges Urbain separated Marignac's ytterbia into two components: neoytterbia and lutecia. Neoytterbia later became known as the element ytterbium, and lutecia became known as the element lutetium. The Austrian chemist Carl Auer von Welsbach independently isolated these elements from ytterbia at about the same time, but he called them aldebaranium and cassiopeium; the American chemist Charles James also independently isolated these elements at about the same time. Urbain and Welsbach accused each other of publishing results based on the other party. The Commission on Atomic Mass, consisting of Frank Wigglesworth Clarke, Wilhelm Ostwald, and Georges Urbain, which was then responsible for the attribution of new element names, settled the dispute in 1909 by granting priority to Urbain and adopting his names as official ones, based on the fact that the separation of lutetium from Marignac's ytterbium was first described by Urbain. After Urbain's names were recognized, neoytterbium was reverted to ytterbium.