Simplify the following text for a Grade 8 native English-speaking person.
Original: The opera is set in Rome and is based on the life of Cola di Rienzi ( 1313 â `` 1354 ) , a medieval Italian populist figure who succeeds in outwitting and then defeating the nobles and their followers and in raising the power of the people .
Simplified: The story of the opera is set in Rome and is based on the life of Cola di Rienzi ( 1313-1354 ) , a medieval Italian populist figure who manages to trick the nobles and their followers . He helps the people to get power .