Complex sentence: Sean Penn won Best Actor and Tim Robbins won Best Supporting Actor, making "Mystic River" the first film to win both awards since "Ben-Hur" in 1959.
Split into simpler sentences: Sean Penn won Best Actor and Tim Robbins won Best Supporting Actor. Most recently, "Mystic River" is the first film to have won both Best Actor and Best Supporting Actor in nearly 44 years after "Ben-Hur" in 1959.