Simplify the following text for a Grade 10 native English-speaking person.
Original: He conducted the Chicago Symphony Orchestra at their summer residence , the Ravinia Festival , for five summers , then became director of the Toronto Symphony from 1965 to 1969 and music director of the San Francisco Symphony from 1970 to 1976 .
Simplified: He was music director of the Toronto Symphony Orchestra from 1965 to 1970 and of the San Francisco Symphony Orchestra from 1969 to 1976 .