1970s: from pre- 'before' + sequel.

• sequel from Late Middle English:

  The earliest use of sequel was ‘a band of followers’. Latin sequi ‘to follow’ is the source, seen also in consequence (Late Middle English) and sequence (Late Middle English), and perhaps in the root of see. Sequel developed the senses ‘what happens afterwards’ and ‘the remaining part of a story’ in the early 16th century. In the 1970s it inspired the prequel, which portrays events that precede those of an existing completed work. From music comes segue [M18] from Italian seguire from sequi. It was originally an instruction in classical music to continue to the next movement without a break, but is now more often found used of moving from one recorded song to another without a break.