Zeus (Greek: Ζεύς): Supreme deity of the ancient Greeks. Adopting Greek mythology, the Romans identified him with Jupiter.
- Originally an Indo-European deity (Greek Zeus = Illyrian Deipaturus, = Latin Jupiter)
- Venerated in Mycenaean times (Linear-B: Po-se-da-o) but still identified with Poseidon
- According to Homer, the "father of gods and men" resides on the mountain Olympus; his wife Hera is the mother of Ares, Hebe, and Hephaestus; Zeus, however, also has children from many other goddesses (e.g., Athena is a daughter of Metis) and from mortal women (e.g., Alcmene's son Heracles)
- Main Greek sanctuaries: Olympia (where the Olympic Games took place) and Dodona (an oracle)
- His attributes: the eagle and the thunderbolt
- Various names: Zeus Chrysaoreus ("of the golden sword"), Zeus Eleutherius, ("Zeus the Liberator"), Zeus Kyrios, Zeus Olympius, Zeus Polieus, Zeus Stratios, Zeus Xenios
- Identified with all kinds of foreign deities, like the Babylonian Marduk, the eastern Ba'al Šamem, the Etruscan Tina, the Libyan Ammon, the Persian Ahuramazda
- The philosopher Cleanthes hailed Zeus as the "first cause who ruled everything through the laws of nature".
- When the Romans adopted Greek mythology, they identified their Jupiter with the Greek Zeus. The Capitoline Triad, the main focus of Rome's state cult, consisted of Jupiter, Minerva (Athena) and Juno (Hera).
- Various names: Jupiter Capitolinus, Jupiter Feretrius, Jupiter Stator, Jupiter Tonans
- Identified with various other foreign deities, like the Jupiter Dolichenus and Elagabal
- In Late Antiquity, Jupiter and Hercules were worshipped as the protectors of the Tetrarchs