Simplify the following text for a Grade 11 native English-speaking person.
Original: This helped to establish the orchestra 's international reputation , and guests Hans Richter , Felix von Weingartner , Richard Strauss , Gustav Mahler , Johannes Brahms and Edvard Grieg conducted the orchestra over the next few years .
Simplified: Other great conductors were also invited to conduct as guests : Hans Richter , Felix von Weingartner , Richard Strauss , Gustav Mahler , Johannes Brahms and Edvard Grieg .