Literature, most generically, is any body of written works.
More restrictively, literature refers to writing considered to be an art form or any single writing deemed to have artistic or intellectual value, often due to deploying language in ways that differ from ordinary usage.
National and tribal sagas, accounts of the origin of the world and of customs, and myths which sometimes carry moral or spiritual messages predominate in the pre-urban eras.
The epics of Homer, dating from the early to middle Iron age, and the great Indian epics of a slightly later period, have more evidence of deliberate literary authorship, surviving like the older myths through oral tradition for long periods before being written down.
Not only is there literature written on each of the aforementioned topics themselves, and how they have evolved throughout history (like a book about the history of economics or a book about evolution and science, for example) but one can also learn about these things in fictional works.
Authors often include historical moments in their works, like when Lord Byron talks about the Spanish and the French in "Childe Harold's Pilgrimage: Canto I" and expresses his opinions through his character Childe Harold.
Its Latin root literatura/litteratura (derived itself from littera: letter or handwriting) was used to refer to all written accounts.
The concept has changed meaning over time to include texts that are spoken or sung (oral literature), and non-written verbal art forms.
As a more urban culture developed, academies provided a means of transmission for speculative and philosophical literature in early civilizations, resulting in the prevalence of literature in Ancient China, Ancient India, Persia and Ancient Greece and Rome.
Many works of earlier periods, even in narrative form, had a covert moral or didactic purpose, such as the Sanskrit Panchatantra or the Metamorphoses of Ovid.