Ancient Greek religion encompasses the collection of beliefs, rituals, and mythology originating in ancient Greece in the form of both popular public religion and cult practices. These groups varied enough for it to be possible to speak of Greek religions or "cults" in the plural, though most of them shared similarities.
Most ancient Greeks recognized the twelve major Olympian gods and goddesses: (Zeus, Hera, Poseidon, Demeter, Athena, Ares, Aphrodite, Apollo, Artemis, Hephaestus, Hermes, and either Hestia or Dionysus), although philosophies such as Stoicism and some forms of Platonism used language that seems to assume a single transcendent deity. The worship of these deities, and several others, was found across the Greek world, though they often have different epithets that distinguished aspects of the deity, and often reflect the absorption of other local deities into the pan-Hellenic scheme. this was on wiki
In many societies, ancient and modern, religion has performed a major role in their development, and the Roman Empire was no different. From the beginning Roman religion was polytheistic. From an initial array of gods and spirits, Rome added to this collection to include both Greek gods as well as a number of foreign cults. As the empire expanded, the Romans refrained from imposing their own religious beliefs upon those they conquered; however, this inclusion must not be misinterpreted as tolerance - this can be seen with their early reaction to the Jewish and Christian population. Eventually, all of their gods would be washed away, gradually replaced by Christianity, and in the eyes of some, this change brought about the decline of the western empire. link here https://www.ancient.eu/Roman_Religion/
