On the Greek side:
Athena
She was the patron of Athens and many other Greek cities. She was also spurned by Paris when he awarded the Gold Apple (which said "To the Fairest" to Aphrodite
Hera
Also rejected by Paris in favor of Aphrodite
Poseidon
When he had his divine powers stripped by Zeus, he and apollo built the walls of Troy, after being promised by Laomedon a handsome payment. When the walls were finished, the king refused to pay. Even though he terrorized the city with a monster, he still held a grudge against the son of the man who slighted him.
HermesIt's never really mentioned why he sided with the Greeks, but it could have been that he felt responsible for the war in a way. He was sent by Zeus to ask Paris to judge the contest of which goddess was fairest, thus setting up the conflict.
Hephaestus
Again, no specific reason is given. It can be assumed that since Hera was on the side of the Greeks, and Hephaestus had an unnatural devotion to his mother, he chose their side for the same reason.
Thetis
As the mother of Achilles, she was naturally sided with the Greeks.
On the Trojan Side:
Aphrodite
She sided with the Trojans because Paris judged her to be the fairest and awarded her the golden apple. She wanted Paris and Helen to be together as a fulfillment of her vow to him, so she helped that happen.
AresThis one is actually weird. The Myrmidons were avid followers of Ares, but he sided against them to favor the Trojans. Probably because Aphrodite did as well.
Apollo
The Trojans were avid sun worshipers, and the Temple to Apollo was a prominent feature on the coast. The sacking of the temple by the Greeks was a major insult to the god who might have otherwise stayed out of it.
Artemis
Fought by the side of her brother.
Zeus
he didn't really take part, but he did favor his daughter, Helen, and her apparent love for Paris.
Leto
As the mother of Apollo and Artemis, a slight on her son was a slight on her.
ErisHaving been snubbed at the wedding of Peleus and Thetis , she still held a grudge against their son, Achilles
Switzerland.
During the Revolutionary War in America, colonists picked sides for a variety of reasons. Some chose one side or another out of loyalty to family or their local community. Some chose sides based on calculations as to who was most likely to win. Some chose sides based on value-commitments and political (and philosophical) ideas; for example, many patriots believed that large, insensitive, oppressive government was a basic evil that must be fought, even if the fight does not promise to be successful.
Greeks learned to plant on hill sides and fish for food.
Greeks learned to plant on hill sides and fish for food.
Greeks and trojans
the Greeks and the trojens
farmed on hill sides
The Greeks and it means 6 sides
The Greeks finally understood Trojans were stalking them by their giant horse.
Greeks versus Persians .
They didn't chose sides because it could get them killed.
The Battle of Marathon was a turning point during the first Persian invasion of Greece. The Persians vastly outnumbered the Greeks on the battlefield, but the Greeks were able to defeat them. The Greeks charged the Persian troops with a thin weaker line, while the Greeks' left and right flanks consisted of stronger troops who quickly surrounded the Persian troops and attacked them on both sides. It was a crushing defeat for the Persians, and the battle convinced the Greeks that while the Persian Empire had vast armies and archers, it was possible to defeat them.