Who is Prince Lothar from Anecdotes of Destiny ; and, Ehrengard and what is their importance?

Prince Lothar appears in Ehrengard. He is the only son of the Duke and Duchess of Babenhausen. Lothar is dedicated to the arts and other studies and completely uninterested in marriage. Taking Herr Cazotte's advice, he woos Princess Ludmilla, but ends up making her pregnant before they are married.