How does Paradise Lost follow conventions from Greek and Roman epic poetry?

John Milton’s Paradise Lost intentionally adopts and adapts several conventions from Greek and Roman epic poetry to establish his work as a biblical epic in English. Key conventions employed include:

• In Medias Res: Following the tradition of Homer and Virgil, Milton begins his narrative in the middle of the action, specifically focusing on the aftermath of the war in heaven before detailing the preceding events.1
• Invocation of the Muse: Milton invokes a "Heav’nly Muse"—the Judaeo-Christian Godhead—to seek inspiration, mirroring the Classical practice of calling upon muses for divine guidance in storytelling.1
• Grand Style and Meter: He utilizes a "grand style" characterized by unrhymed iambic pentameter, or blank verse, which he intended to approximate the heroic verse of Homer and Virgil.1
• Epic Similes: The poem features protracted, explicit comparisons introduced by "like" or "as," a hallmark of the Classical epic tradition.1
• Underworld Descent: The narrative includes a descent into hell, echoing the Classical epic convention of a journey into the underworld.1

While Milton utilizes these forms, he also seeks to "debunk" Classical heroism—often defined by pride and battlefield valor—by promoting a Christian ideal of heroism centered on self-sacrificing love, patience, and fortitude.1