Simplify the following text for a Grade 9 native English-speaking person.
Original: Muawiyah , a relative of Uthman and governor ( Wali ) of Syria , became one of Ali 's challengers and after Ali 's death managed to overcome the other claimants to the Caliphate .
Simplified: Muawiyah , a relative of Uthman , and governor ( Wali ) of Syria became one of Ali 's challengers . After Ali 's death he became Caliph .