Complex sentence: In 1721, Louis XV was betrothed to his first cousin, the Infanta Maria Anna Victoria of Spain, but the eleven-year-old king was not interested in the arrival of his future wife, the three-year-old Spanish Infanta.
Split into simpler sentences: In 1721, Louis XV at the age of 11 was betrothed to his first cousin, the Infanta Maria Anna Victoria of Spain. The eleven-year-old king was not interested in the arrival of his future wife, the three-year-old Spanish Infanta.