The main hero of the story, Odysseus, lived in Ithaca and was its rightful ruler. Homer described it as being "low-lying" and farthest to the west, despite being mountainous, and the island of Kefalonia being even more to the west. Some scholars argue that Homer's Ithaca was not modern-day Ithaca, but rather a nearby island. Odysseus was one of the suitors of Helen, the most beautiful woman in the known world. Foreseeing that the situation would not lead anywhere, as there was a multitude of suitors and Tyndareus was unable to choose a husband for her in fear of offending them, he made a proposal to him. He said that if Tyndareus would help him win the hand of Penelope, then he would provide a solution to the problem. He then told all of the suitors to swear an oath, which was hence named the Oath of Tyndareus, according to which no matter who Helen would pick for her husband, they would all support the couple. Everyone agreed and Helen chose Menelaus, king of Sparta. Odysseus then took Penelope for his bride and went back to Ithaca.
After Helen's abduction by Paris and before the Trojan War started, Odysseus was told by an oracle that if he went to the expedition to retrieve Helen, he would not return home for decades. So, he originally pretended to be insane, but his plan was foiled and he was forced to join the Greek army against the Trojans. After the Trojan War, which lasted ten years, it took him another ten years to return home, facing multiple adventures in the process.