Simplify the following text for a Grade 9 native English-speaking person.
Original: It is during this era of the Marathi theater that great singer-actors like Bal Gandharva , Keshavrao Bhosle , Bhaurao Kolhatkar and Deenanath Mangeshkar thrived .
Simplified: Important actors at this time were Bal Gandharva , Keshavrao Bhosle , Bhaurao Kolhatkar , and Dinanath Mangeshkar .