The ancient Greek gods are composed of many deities, minor and major. There are literally hundreds of minor ones. When Northern nomads raided small settlements predating the city-states, the population continued to worship their deities, with a central mother goddess figure. Nomads relied on weather gods like Zeus. To unite conflicting theologies, the gods representing weather would be married to the town’s mother goddess, which promoted harmony in worship and caused less resistance among the conquered townspeople.
This explanation will focus on the twelve major ancient Greek gods, called by the Greeks the Olympian gods, which came to be recognized as the most important deities, and were thence worshipped by the Romans prior to Christian conversion. Six of the gods were the offspring of the titan siblings, Cronus and Rhea, but only four of them ruled in Olympus. Hades rules the Underworld, and Poseidon is the god of the sea. Both are among the major twelve, but make their homes elsewhere.
Cronus swallowed his children to prevent them from stealing his power. Rhea was able to hide Zeus from Cronus, and he was raised on Crete. Upon reaching maturity, Zeus forced Cronus to disgorge his five elder siblings. This led to the war with the Titans, in which Zeus and his siblings wrested with the Titans and gained control of Mount Olympus.
Zeus, the supreme ruler of Olympus and the leader of the ancient Greek gods, controls the weather, especially fierce weather, when he hurls lightning bolts from the sky. Zeus has children with a number of goddesses and mortals, which infuriated his wife and sister Hera, who would often exact retribution. These liaisons are explained by the barbarian takeovers of small settlements that worshipped a mother goddess. Hera is also a protector of women, mothers and wives, linked with domesticity.
Hera and Zeus produced Ares, or Mars, god of war. Mars is significant in Homer’s Iliad. He also had an affair with his half sister Aphrodite, much to the chagrin of Aphrodite’s husband Hephaestus.
Hephaestus is blacksmith for the gods and sibling to Ares. He is connected with fire and metal, and makes the lightening bolts thrown by Zeus. He is depicted as lame or hobbled. This hobbling is based on the actual practice of crippling skilled smiths to prevent them for leaving an area. Hephaestus, by way of compensation, is married to Aphrodite.
Aphrodite has two mythological origins as one of the ancient Greek gods. She is either the daughter of Zeus and a minor goddess, or she arose from sea foam caused by the blood of Uranus. She is the quintessential goddess of love and beauty, also the mother of Eros. While some worshipped her, especially unrequited lovers, she is often thought to be mischievous; her reward of Helen to Paris caused the Trojan War.
Zeus and Latona’s children Apollo and Artemis are twins. Apollo is the god of justice, wisdom and prophecy. He is linked to the sun, which he is said to love, and is also the inspiration for athletic contests. Among the gods, he is one of the best loved, as he tends to represent fairness and joy.
Artemis is the goddess of the hunt, though she is also sometimes associated with childbirth. She remains virginal and was worshipped by maidens. In contrast to Apollo, she is closely associated with the moon.
Athena is said to have sprung from the brow of Zeus. She is the maiden warrior, but also represents wisdom and intellect. She shares control of storms with Zeus, and control of war with Ares. Among the ancient Greek gods, she is one of the most involved players in the Trojan War as depicted in the Iliad.
Hermes is son to Zeus and Maia. He is known for his swift feet and was messenger to the gods. He is the patron of chance and gamblers, known for his practical jokes. He is also the conductor of souls to the underworld.
Hestia is the first child of Cronus and Rhea. She is the household goddess, important in all things domestic. She is also associated with the harvest, although she shares that duty with Demeter, Zeus’ sister, the true goddess of the harvest and last of the Olympian rulers.
Greeks honored all the ancient Greek gods, but could worship one more than the others mostly by personal choice. Fisherman might give their first allegiance to Poseidon, and soldiers would likely honor Ares and Athena. Farmers were likely to honor Demeter above others. Senators might most praise Apollo and Athena.