Simplify the following text for a Grade 10 native English-speaking person.
Original: The Royal Ballet is an internationally renowned classical ballet company , based at the Royal Opera House in Covent Garden , London , England . The largest of the three major ballet companies in Great Britain , the Royal Ballet was founded in 1931 by Dame Ninette de Valois , it became the resident ballet company of the Royal Opera House in 1946 and was granted a Royal Charter in 1956 , becoming recognized as Britain 's flagship national ballet company .
Simplified: These would become the predecessors of today 's Royal Ballet , Birmingham Royal Ballet and Royal Ballet School .