What is Jacob Sartorius' middle name?

Explanation

Jacob Sartorius was born in Oklahoma on 2nd October 2002. His birhtname is Rolf Jacob Sartorius, named after his father and grandfather who are both called Rolf. Jacob said that the name Rolf has been a tradition in his family, but he doesn’t like to go by that name. His star sign is Libra and he was born in the Chinese year of the horse.