This may sometimes be confusing, as descendants of nobles are sometimes referred to with noble names abroad. Also, members of noble families often hold multiple citizenships, as was the case for Otto von Habsburg (eldest son of the last Emperor of Austria-Hungary and father of Karl Habsburg-Lothringen), who was also a citizen of Germany. The Austrian law does not apply to artistic, performer or stage names, where "von" is sometimes used, as in the case of conductor Herbert von Karajan or the musician Hubert von Goisern. However, stage names are never recognized for official purposes.