Simplify the following text for a Grade 11 native English-speaking person.
Original: In 1958 he won the international Koussevitsky Competition for conductors , which resulted in a number of operatic conducting engagements in Italy , and in 1963 he won the Dimitri Mitropoulos Prize for conductors , allowing him to work for five months with the New York Philharmonic .
Simplified: In 1958 , he won the international Koussevitsky competition for conductors .