Simplify the following text for a Grade 6 native English-speaking person.
Original: The Asaf Jah dynasty had only seven rulers ; however there was a period of 13 years after the rule of the first Nizam when three of his sons ( Nasir Jung , Muzafar Jung and Salabath Jung ) ruled .
Simplified: The Asaf Jah dynasty had only seven rulers . However , for 13 years after the rule of the first Nizam , three of his sons ( Nasir Jung , Muzafar Jung and Salabath Jung ) ruled .