The Greek's won the Trojan war by tricking the roman's into thinking they surrendered and they sneaked into the walls to kill them.
Odysseus and his crew were captured by a cyclops so he defeated him by gouging his eye out, but of course Odysseus being big headed his egotistic self had to tell the cyclops who had defeated him.
you have been defeated by Odysseus.
Poseidon was outraged by the fact that his son got his eye gouged out and disrespected by Odysseus who was supported by Zeus and cursed him so he would have a rough journey home.
Odysseus and his crew saw the curse Poseidon had sent them for gouging his son's eye out.
After Athena finds him on the shore and sends him to his homeland with a protective mist around him so he can't recognize his homeland. Finally after he arrives Athena appears and takes the mist off him and makes him look like an old man as disguise.
Penelope notices that a maid is in her room and the bed is moved and that is how she realizes Odysseus is home.