Complex sentence: He founded the Riverside Studios in Hammersmith in 1976; associate director of the National Theatre 1980-1997, he also founded the National Theatre Studio in 1984, which he ran until 1990.
Split into simpler sentences: He founded the Riverside Studios in Hammersmith in 1976. As an associate director of the National Theatre 1980-1997, he also founded the National Theatre Studio in 1984, which he ran until 1990.