Complex sentence: Roger Corman had been interested in making a film about Von Richthofen for a number of years-in 1965 it was announced he had commissioned a script called "The Red Baron" from Robert Towne.
Split into simpler sentences: Roger Corman had been interested in making a film about Von Richthofen for a number of years. In 1965 it was announced he had commissioned a script called "The Red Baron" from Robert Towne.