Simplify the following text for a Grade 9 native English-speaking person.
Original: Bach inscribed the piece `` Regis Iussu Cantio Et Reliqua Canonica Arte Resoluta '' ( the theme given by the king , with additions , resolved in the canonic style ) , the first letters of which spell out the word ricercar , a well-known genre of the time .
Simplified: At the top of the music Bach wrote some Latin words : `` Regis Iussu Cantio Et Reliqua Canonica Arte Resoluta '' ( this means : â the theme given by the king , with additions , resolved in the canonic styleâ ) . The first letters of these words spell out the word ricercar , which was a form of music well-known at the time .