While Nolan took some poetic license in his version of the story (much to the chagrin of Emily Wilson, among others, who published a highly praised translation of Homer's epic poem in 2017), I do think that he stayed true to some of the major themes in the original work (at least in my humble and admittedly non-expert opinion). At its most basic, The Odyssey is a story of a man who has lost his way and who eventually finds his way back home. In Nolan's version of the story, Odysseus is lost almost by choice. He feels guilty about the fact that he was the one that came up with the idea of the Trojan Horse to "trick" the people of Troy to let the Greeks in through the gates of their city and eventually destroy it.
Eliana Dockterman writes in her Time magazine review, "Odysseus, much like the father of the atomic bomb millennia later [is] wracked with guilt for conjuring something that destroyed not just one city but, in his mind, an entire civilization: the Trojan Horse. In creating the vessel in which the Greeks hid to penetrate the walls of Troy and massacre its citizens to ultimately win the war, Odysseus believes he violated what characters throughout the movie refer to as Zeus’ Law. In doing so, he then gave tacit permission for others throughout the Mediterranean to break the rules that long held this ancient civilization together."
It is this violation of the ancient Greek law known as xenia that is the source of Odysseus' guilt. Xenia means hospitality, and refers to the moral obligation to treat even complete strangers as guests in your home. Xenia was known as Zeus' law, because Zeus was the patron god of strangers. His law dictated that strangers must be welcomed with food, shelter, and respect. If you consider that ancient Greece was really comprised of several islands and city-states, a law like xenia makes perfect sense. If you ever found yourself stranded on one of those islands, you would want to be treated with kindness and offered food and shelter. Bear in mind that the ancient Greeks believed too that the gods often mingled among the people, even showing up as strangers at the door to someone's home. Treating a stranger kindly (unkindly) could earn a divine reward (punishment).
The Golden Rule from the Christian tradition sounds very similar to xenia and states, "Do unto others as you would have them do unto you." The ancient Greek law of hospitality took things even one step further. Guests were expected to reciprocate that kindness, trust, and respect that was showed to them. Guests were also prohibited from taking advantage of the hosts' kindness. Those who violated Zeus' law received divine punishment. Odysseus felt his punishment for violating xenia was to wander for 10 years in search for home. It is only after he forgives himself and then asks for forgiveness from the goddess Athena, that Odysseus finds his way back home.
One additional theme that recurs throughout the movie is that of loyalty. Odysseus wife and son, Penelope (played by Anne Hathaway) and Telemachus (played by Tom Holland) stay true to Odysseus, hoping and expecting that he will return, even after 10 years without hearing anything about him. Both fight off Penelope's treacherous suitors, who constantly plot against them in an attempt to usurp Odysseus' throne. Odysseus swineherd, Eumaeus (played by John Leguizamo) helps them both and remains loyal to Odysseus until the very end, as does Odysseus beloved and faithful dog, Argos, who dies after seeing his master one last time.
Leadership is a lot about trustworthiness, loyalty, perseverance, resilience, and ultimately, xenia.


