Simplify the following text for a Grade 10 native English-speaking person.
Original: In 1999 , he was appointed music director of the Orquesta SinfÃ nica SimÃ n BolÃ var , the national youth orchestra of Venezuela , and toured several countries .
Simplified: In 1999 , he became music director of the Orquesta SinfÃ nica SimÃ n BolÃ var , the national youth orchestra of Venezuela , and toured several countries .