In religion, the blending of two or more religions is known as Religious Syncretism
, and frequently results in an apparent religious expy, especially when two different deities become identified with each other and merged into one entity; nearly every example below stems from this effect.
- Quite a bit Older Than They Think - due to the ancestral speakers of Indo-European languages expanding across Europe and Asia, the languages (and Gods) of a whole lot of cultures have the same origins. Looking at the Norse, Greek and Hindu pantheons, it's possible to find quite a few parallels among the old gods and their myths. (For example, an ancient Hindu sky god named Dyaus, the Greek Zeus and the Roman Jupiter are essentially the same god, with a few changes along the way and over the years)
- Many Catholic festivals were adapted from local ones to make Christianity more welcoming. Some Saints were contemporaries of the pagans that they converted. Others were adapted deities.
- Roman gods and goddesses were Expies of Greek gods and goddesses (such as Jupiter and Zeus, Venus and Aphrodite, Juno and Hera, Vulcan and Hephaestus, etc.)
- This is not strictly true as many of the Roman gods (notably Mars and Vesta) have different connotations and importance than their Greek counterparts. In the long run, it's more of a Hijacked by Jesus thing - the originally distinct Roman deities became, to varying degrees, assimilated with the Greek deities they were identified with.
- There is also the fact that the Romans were notorious for bringing in gods from other religions when they needed something new as well as finding commonalities with the religions of new people they "brought" into the empire. It was a great way to create a loyalty to the empire "Ahh see this is Jove by a different name. Carry on, just don't forget to pay the proper homages."
- Many of the Greek gods themselves have origins in earlier religions. Aphrodite is a clear Expy of the Babylonian goddess Ishtar, who herself is an Expy of the Sumerian Inanna. The mythological figure Adonis is believed to have been adapted from the Sumerian god Tammuz, whose title was Adon ("lord" in Semitic languages).
- The very reason Romans were suspicious of Jews and outright hostile to Christians for so long was because neither were willing to pay lip service to Roman gods (both movements being monotheists at that point).
- The Hijacked by Jesus variant is the same reason the gods of Egyptian Mythology have so many names—they absorbed the qualities of less popular gods and worshipers later said that these lesser gods were merely "aspects" of them.
- Dayconawega, the American First Nations Jesus. Virgin mother, Disciples, and Back from the Dead.
- Aeneas to Achilles, very deliberately and almost to the point of a Whole Plot Reference. A few of the more blantant examples: Achilles had an unbreakable shield made by Hephaestus with images of the world on it, Aeneas had an unbreakable shield made by Vulcan with images of Rome on it. Achilles best friend is killed by the leader of the opposing side in a war, and he responds by not just defeating the man in single combat with a spear, but humiliating and ultimately killing him. Guess what?
- Ereshkigal of Mesopotamian Mythology. She is the underworld equivalent of the fertility goddess Inanna (Ishtar), said to be her younger twin. In fact, they may have at one point been two aspects of the same goddess before becoming separate entities.