In Greek mythology, Zeus is the god of the sky and thunder (among other things), and presides over the Olympian pantheon. He is represented by the thunderbolt (or lightning), the eagle, the bull, and the oak tree. Among other relationships, he is the son of Cronus, the husband of Hera, and the brother of Hades and Poseidon. Some consider Zeus the foremost identifiable persona in all Greek mythology.
Jupiter is the Roman counterpart to Zeus. Like Zeus, Jupiter was the god of the sky and thunder, and he was also represented by an eagle. Sometimes this symbolism overlapped and he was depicted by an eagle holding thunderbolts, which was an image that was sometimes displayed on Greco-Roman coins.
Zeus is the youngest son of Cronus, his father, and Rhea, his mother. He was married to Hera, who was also his sister. According to Homer's The Iliad, Zeus is also the father of Aphrodite, who was born to Dione. Zeus is known for his erotic exploits, which produced many children, including Athena. And even though he didn't produce all Greek gods, most deities call Zeus "father," which speaks to his position in the pantheon.
Zeus: birth and rise to prominence
A brief biography
Cronus, Zeus' father, threatened his life at birth, like he did his other children, fearing a prophecy that said one of his children would usurp his power. In order to protect him, Zeus' mother, Rhea, along with Gaia (i.e. Earth personified), came up with a plan to save him. When Zeus was born, Rhea wrapped a rock in swaddling clothes, meant to look like a newborn baby. She then gave the rock to Cronus who was fooled and ate it. Rhea then hid Zeus in a cave in Crete. One story says that when Zeus cried, other gods would make loud noises with their spears and shields, so Cronus wouldn't hear it and find him and eat him.
How did Zeus get to be the chief god?
When Zeus grew up, he forced his father Cronus to release his siblings. (Different stories have different descriptions of this.) Zeus then forced Cronus to release his uncles (i.e. Cronus brothers) from Tartarus, including the Cyclopes. The Cyclopes, in turn, gave Zeus thunder and lightning, which, at the time, were being hidden by Gaia.
Zeus eventually physically overthrew Cronus, who was tossed into Tartarus. One god who fought against Zeus at this time, Atlas, was punished by having to hold up the sky. After the conflict was over, Zeus and his brothers acquired different jurisdictions: Hades got the underworld, Poseidon got the sea, and Zeus got the sky. Gaia was part of all three realms.
Who was Hera? Hera is Zeus' sister and his wife. Several stories, however, tell of Zeus' exploits with other female deities like Demeter. Hera is also represented as jealous of Zeus' relationships and an enemy of his mistresses.
Zeus in Judeo-Christian literature
Zeus is mentioned two times in the New Testament; both references are in the book of Acts. In Acts 14:8-13, the Apostle Paul heals a disabled man in Lystra, a place which some historians have noted was known for devotion to Zeus. Witnesses of the healing think Paul and his companion Barnabas are Greek gods in human form. Specifically, they believe Paul is Hermes and that Barnabas is Zeus. The people of Lystra even tried to offer sacrifices to them before Paul and Barnabas stopped them.
The second reference to Zeus is in Acts 28:11, where Paul and others are sailing from Malta onboard a ship. The ship contained a physical representation of the "sons of Zeus," Castor and Pollux.
In the Deutero-cananoical (or apocryphal book), 2 Maccabees 6:1-2, the written refers to Antiochus Epiphanes (or Antiochius IV) seeking to eradicate Judaism from the region and rededicate their sacred temple to Zeus.
The Bible, KJV version