An epic poem is a poetic narrative about an important event, usually were protagoniyed by a hero who must achieve something successfully in order to maintain the common order. Before the development of writing, epic poems were memorized and played an important part in preserving a record of the activities and history of a culture.
John Milton: Paradise Lost. It narrates the temptation of Adam and Eve by Satan and their expulsion from the Garden of Eden.
Edmund Spenser: The Faerie Queene. It was supposed to have been a religious-moral-political metaphor in 12 books, each consisting of the adventures of a explorer characterizing a particular moral virtue; Book I, for example, narrates the legend of the Red Cross Knight.
Virgil: The Aeneid. It narrates the story of Aeneas who travelled to Italy to become the ancestor of the Romans.