The Odyssey is one of the oldest pieces of literature still read today. Divided into 24 books, the epic poem tells the story of Odysseus, the king of the island of Ithaca, and his 10-year-long journey back home, following the 10-year-long Trojan War.

Along the way, Odysseus's ships are destroyed by storms, he’s imprisoned for seven years, travels to the underworld, fights various giants, monsters and gods. The word odyssey—defined as "a long wandering or voyage usually marked by many changes of fortune'—is derived from the name of the Greek epic.

The ancient Greek poet Homer is attributed as the author of the Iliad, set towards the end of the Trojan War, and the Odyssey, although scholars aren’t sure whether Homer actually existed. Some have suggested Homer was rather a concept and the works were shared orally and then written down in poetic form for performance in the second half of the 8th century B.C.

“A lot of critics consider the Odyssey to be a lesser piece of work because it has all these fantastical elements,” says Hans Bjork, an Assistant Professor of Classics at Stanford University.

But Bjork argues that the complicated portrayal of Odysseus makes the Odyssey much more relatable to modern readers, as he acts as a warning for the different types of trouble people can get into.

For example, when he and his men sail past the sirens—winged, part-bird, part-woman creatures that lure sailors to their deaths with their music—Odysseus can't resist listening to their song.

“Odysseus is so curious about everything. When they go past the sirens his men tell him to sail around. But he tells them to put wax and cotton in their ears and tie him to the mast so he can hear what it’s like,” Bjork says.

Here are five key facts about the Odyssey’s protagonist.

Bjork argues that Odysseus is one of the most prolific figures in ancient myth. Not only is he a key figure in the Iliad and the main character of the Odyssey, but he shows up again in the plays of Aeschylus, Sophocles and Euripides, and in works from the Hellenistic period.

What makes Odysseus such an integral literary figure, though, is his longevity. Over the next few centuries, during the Roman Empire and the Middle Ages, stories of Odysseus continued to be told. Even in the last 200 years, poet Alfred, Lord Tennyson and writers James Joyce, Nikos Kazantzakis and Margaret Atwood have all used the Odyssey and Odysseus as inspiration, proving that the character remains as fascinating and prescient as ever.

Odysseus’ influence is still felt because, unlike other Greek heroes like Achilles, Perseus and Heracles, he’s known for being smart and insightful, rather than as a powerful fighter. Bjork calls Odysseus “extremely savvy.”

“Throughout the stories, there’s a persistent theme of him hiding his identity, pretending to be other people, and tricking individuals to get his way,” says Bjork, who notes that Odysseus’ role in the stories was to figure out how to complete a difficult task.

“He’s a chameleon. That’s what makes him so appealing as a literary figure.”

Odysseus is hard to pin down as a character because he’s put through so many different situations and scenarios in the Iliad and Odyssey. At times he’s very noble, but there are other occasions when his acts are cruel, bloody and unpleasant. Bjork believes that he wasn’t even “a great leader of men, as they are constantly getting into trouble and causing problems that he then has to try and fix.”

“There’s a feeling of discomfort with Odysseus that often comes with the most interesting characters,” remarks Bjork. Reading about how Odysseus encounters and handles adversity pulls readers in.

During his 10-year journey to get back to Ithaca, Odysseus has to overcome various monsters. His most famous encounter in the Odyssey is with Polyphemus, a cyclops, who traps Odysseus and his men and takes them captive. Polyphemus starts to eat his men, and promises to devour them all. But Odysseus gets away through trickery. “He basically gets Polyphemus very drunk," explains Bjork. "Then when he’s passed out Odysseus shoves a stake through his eye and blinds him.”

But there are consequences to Odysseus’ attack on Polyphemus. Poseidon, who is related to Polyphemus, and is the God of the sea, prolongs Odysseus’ journey back to Ithaca by creating storms and waves that destroy his raft.

Over the course of his journey, Odysseus also encounters Aeolus, the God of the winds, who gives him a bag that contains all of the winds, except for the west wind that would take him back to Ithaca. He also narrowly avoids a group of cannibals.

Many of Odysseus’ men are turned into pigs by Circe, a sorceress. He uses the herb moly to convince Circe to turn his men back into humans. Circe and Odysseus then have a year-long affair, which results in her giving birth to two sons. Plus, Odysseus sails past Charybdis, a giant whirlpool that sucks ships down, and Scylla, a six-headed monster, who snatches six sailors from Odysseus’ ship after it gets too close.

Arguably the most famous story to emerge from Greek mythology is that of the Trojan Horse. After fighting the Trojan War for years, the Greeks build a giant wooden horse seemingly as a gift for the Gods, and left it outside the gates of Troy. When the Trojans bring the horse inside, Greek soldiers emerge from it later that night, open up the city gates, and the rest of the army enters. They destroy the city and defeat the Trojans.

The likes of Achilles, Agamemnon, Helen of Troy and Paris might be the most famous characters from the Trojan War, but Odysseus is believed to have come up with the idea.

While the tale is the ultimate example of Odysseus’s cleverness, trickery and effectiveness, it’s also a reminder of how dark he was. “Sure, it’s fun,” notes Bjork, “but it still led to this massive slaughter and the enslavement of an entire city.”

Margaret Atwood’s 2005 novella The Penelopiad, which retells the events of the Odyssey from the perspective of Odysseus’ wife Penelope, paints him as more of a villainous figure. “It punctures the ideas around [his] heroism,” says Bjork. “It interrogates the dark parts of the story that we tend to overlook because Odysseus is so charming.”

The Odyssey has been interpreted in many different ways since it was published between 2,670 and 2,770 years ago. For some it’s about resilience and making it back to your family at all cost, as well as a story about loyalty, hospitality and the role of Gods.

For others, though, the work speaks to the psychological impact and trauma of war. When Odysseus starts to tell people about what happened to him during the Trojan War, he begins to weep. In the 1960s and 1970s, with the Vietnam War raging, many scholars started to see the poem as an exploration of how his “behavior and decision-making relates to PTSD,” says Bjork.

Odysseus is an enduring character because there are so many different ways to analyze his story, adds Bjork. “Depending on the source, you have really different perspectives on Odysseus," he says. "He’s a very clever hero, but sometimes he’s a ruthless villain.”