retrospective

Concise Oxford English Dictionary © 2008 Oxford University Press:
retrospective/retrəˈspektɪv/

▶adjective

• 1 looking back on or dealing with past events or situations.

  ■ (of an exhibition or compilation) showing the development of an artist's work over a period of time.

• 2 (of a statute or legal decision) taking effect from a date in the past.

▶noun a retrospective exhibition or compilation.

– derivatives
retrospectively adverb.