Iliad vs. Odyssey

(italics),  a Greek epic poem describing the siege of Troy, ascribed to Homer.

(sometimes lowercase),  any similar poem; a long narrative.

(often lowercase),  a long series of woes, trials, etc.

(italics),  an epic poem attributed to Homer, describing Odysseus's adventures in his ten-year attempt to return home to Ithaca after the Trojan War.

(often lowercase),  a long series of wanderings or adventures, especially when filled with notable experiences, hardships, etc.