Simplify the following text for a Grade 7 native English-speaking person.
Original: It is said to have become the official dog of the House of Orange in 1572 after a pug named Pompey saved the life of the Prince of Orange by alerting him to the approach of assassins .
Simplified: Later , in 1572 , a pug named Pompey saved the Prince of Orange by warning him when the Spaniards came .