Complex sentence: He cast Jeroen Krabbé in his first major role to play Guus LeJeune, the friend of Hazelhoff Roelfzema's character, which was based on Ernst De Jonge and Peter Tazelaar.
Split into simpler sentences: He cast Jeroen Krabbé in his first major role to play Guus LeJeune, the friend of Hazelhoff Roelfzema's character. The role was based on a combination of Ernst De Jonge and Peter Tazelaar.