Conversation so far:
when was the last time man united were in the champions league
Manchester United were last in the Champions League during the 2018 - 2019 season.
When was the last time Arsenal were in the Champions League?
Arsenal were last in the Champions League during the 2016 - 2017 season.
When was the last time A.C. Milan were in the Champions League?
A.C. Milan were last in the Champions League during the 2013 - 2014 season.

Question: Was Monaco in Europe?
Self-contained rewrite: When was the last time Monaco were in the Champions League?