A charming friend who could be a terrible person...who when she died got transformed into "our wonderful kind understanding etc., etc.," Or all the things she wasn't in flesh and blood. In real life she would stand you up...let you down...lie...etc., etc. I had a dream that I went into a shop and asked for "...a Map of Death please!" and the shopkeeper said he had just sold the last one to my friend. Hence the poem that came about that told what she had been really like but through the medium of maps.
Obviously when you write a poem you chose the balance of mood and words and what to leave in and what to leave out so that you focus on whatever emotional trajectory you come in on and that gives you the mental landscape of what you have elected to view.
Come in on a different emotional trajectory and you get a completely different landscape of the mind...a whole new planet Poem. So the backstory may be left out until you have to tell it or fill it out or write a different poem. Going to a reading in ParisΒ Β and learning that the theme has to be of death and its whatfors and wherefors... meant that this poem which I happened to have in my possession suddenly forced the background story to the forefront...so the explanation comes about 2 years after the writing of the poem. In time this backstory or the view of the story as seen from this point of perspective may in itself become the poem that eclipses this one in a total eclipse of the art.