Complex sentence: Her father, however, disagreed because of the bad reputation of Honoré as well as the prospect of Honoré inheriting his fortune, but after intervention by Louis XV and Madame de Pompadour, he gave his consent in 1757.
Split into simpler sentences: Her father, however, disagreed because of the bad reputation of Prince Honoré as well as the prospect of the prince inheriting his fortune. He relented only after intervention by Louis XV and Madame de Pompadour, giving his consent in 1757.