Simplify the following text for a Grade 11 native English-speaking person.
Original: The production at Rome of his opera Gli Equivoci nell sembiante ( 1679 ) gained him the support of Queen Christina of Sweden ( who at the time was living in Rome ) , and he became her Maestro di Cappella .
Simplified: When his opera Gli Equivoci nell sembiante was produced in Rome in 1679 the Queen of Sweden , who was living in Rome at the time , was very impressed and gave him the job of being her Maestro di cappella .