Complex sentence: It is the third in his BRD Trilogy: the previous films are "The Marriage of Maria Braun" (BRD 1) and "Veronika Voss" (BRD 2).
Split into simpler sentences: It is the third in his BRD Trilogy. The other films are "The Marriage of Maria Braun" (BRD 1) and "Veronika Voss" (BRD 2).