Simplify the following text for a Grade 10 native English-speaking person.
Original: Although it is one of the few battles specifically mentioned in the Muslim holy book , the Qur ` an , virtually all contemporary knowledge of the battle at Badr comes from traditional Islamic accounts , both hadiths and biographies of Muhammad , written decades after the battle .
Simplified: It is one of the few battles specifically mentioned in the Quran . Most contemporary knowledge of the battle at Badr comes from traditional Islamic accounts , both hadiths and biographies of Muhammad , some written after the battle .