Duke of Royan from 1745 to 1789
His Highness Prince Louis Augustin was born on July 11, 1707, he is the first child of the ducal couple, Prince Augustin (1686-1745) and Anne-Marie Lassère.
He married Jean Laurin with whom he had: Princess Marie (c. 1747-1781), Princess Geneviève (c. 1750-1792), Princess Christine (c. 1750-1838) and Prince Pierre.
The Prince died on December 7, 1789. His grandson, Germain, became Duke of Royan.