The epic is a broadly defined genre of narrative poetry, characterized by great length, multiple settings, large numbers of characters, or long span of time involved. As a result of this change in the use of the word, many prose works of the past may be retroactively called "epics" which were not composed or originally understood as such. A work need not be written to qualify as an epic, although even the works of such great poets as Homer, Dante, and Milton would be unlikely to have survived without being written down.