Imparfait vs passe compose

Question

Mon chien favorit s'appelait Pip.  Why the imparfait here?  It seems a simple statement, neither ongoing, repeated nor descriptive.  It doesn't seem to fulfill any of the criteria of the imparfait.

Maarten Kamp · Accepted Answer

This is a piece of background history, and is ‘descriptive’ in that sense. It was not a specific single event, or series of completed events. It was an ongoing ‘action/event’ completely in the past - maybe arguing in circles here, but the use of imparfait in French actually tells us that.
As well as the lessons here, the attached is a good link for developing a feel for the French use of imparfait - recommend reading through the story examples and watch the video explanation. 
  https://www.frenchtoday.com/blog/french-verb-conjugation/passe-compose-versus-imparfait/

Dave Moore · Answer

My understanding, in this case, would be that the dog was called Pip for its entire life, not for just one moment in time. I may well be quite wrong.