Here's what to consider:
* Short narrative poems: These might be only a few lines long, focusing on a single event or a simple story. Think of a haiku or a limerick, which are often considered narrative forms.
* Epic poems: These are much longer, sometimes spanning thousands of lines. Think of "The Odyssey" by Homer or "The Aeneid" by Virgil.
* Modern narrative poems: These can range in length, from short poems to novels written in verse.
Instead of focusing on the number of lines, it's more helpful to look at the characteristics of a narrative poem:
* Tells a story: It has a clear beginning, middle, and end.
* Develops characters: Readers can identify with the characters and their journeys.
* Uses vivid imagery: The language creates a strong sense of place and atmosphere.
* Often uses rhyme and meter: Though not always required, these elements add rhythm and musicality.
Ultimately, the number of lines in a narrative poem isn't as important as the story it tells and the impact it has on the reader.