In The Odyssey, which two gods were the Greeks' allies?
In this story, the gods and goddesses play a huge part in Odysseus’ journey. Some gods were on the Greeks' side and others worked against them. Wherever they went a god or goddess was always watching over them. For good or badl, Athena, Poseidon, and Zeus all worked upon Odysseus’ long journey.
The goddess Athena helped Odysseus through many adventures on his journey. She was the goddess of crafts, domestic arts, and war. She watched over him constantly and Odysseus prayed to Athena for help or comfort. Athena helped him beat the suitors at the end of the story and regain his wife and home. She disguised him so he could sneak home unrecognized, so he could find out who was still truly loyal to him. Athena prevented the suitors from killing him.
Some have said that Athena treats Odysseus like a fellow god, almost as an equal, and that this indicates that he has a high status among mortal men--almost a god himself and equal to the great and powerful Athena.
Athena has a unique part to play in the story. She is the only god who directly intervenes in the plot on the Greeks' behalf. Poseidon also intervenes, but he is holding a grudge and therefore does not help the Greeks.
The other god who could be said to ally himself with the Greeks is Zeus, Athena's father. Although he does not directly interact with the Greeks, hedoes respond to Athena's pleas for him to help the Greeks. As Zeus is the king of the gods, the others obey his commands, even though they may not want to carry out his requests.
In the beginning, Zeus gives Athena permission to begin arrangements for Odysseus's return.
Later, Zeus tells Hermes to go to Calypso and tell her to let Odysseus leave for Ithaca. Calypso is unhappy, but obeys the order.
Zeus can sometimes punish the Greeks for disobediance, too. Once he orders the sailors not to harm the cattle of the sun-god on the island of Thrinacia. However, since they are out of food, Odysseus's men kill some of the cattle anyway. The sun god complains to Zeus. In retaliation, Zeus destroys the ship with a thunderbolt. Only Odysseus survives to return to Ithaca.
At the end, Athena and Zeus intervene in the fighting and after several of the suitors' relatives are killed, Athena brings peace.
I haven't read The Odyssey in years, unfortunately, but I think I'm still able to contribute to this discussion. I'm sure that Athena is one of the strongest allies among the Gods. She's the patron of Athens, after all.
The building of a wooden horse makes me suspect that the Greeks' second strongest ally among the gods was Poseidon, who's affiliated not just with the oceans but also with horses (hence, we can find all kinds of wonderful portrayals in painting of the sea's crashing waves turning into charging horses).
A check of online sources confirms my suspicions:
"Athena and Poseidon were two of the most powerful allies of the Greek forces throughout the war. However, the failure of most of the Greek leaders to punish Ajax the Lesser for the sacrilege of her (Athena's) altar, resulted in the destruction of most of the Greek fleet." (see timelessmyths.com, the source cited below)
Poseidon, too, is angered and keeps Odysseus from finding his way home for years and years after Troy has fallen. The Greek gods can be fickle.