Mmm . . . kind of a loaded question.
The short answer is “no.”
I think I would rather say—cautiously—that the Christians, of late-Roman times and up through the Middle Ages, took various pagan gods—notably Pan, Dionysus, Herne the Hunter, and Cernunnos and shaped them into what became the Christian devil. The Church was locked in a pretty desperate struggle in the early days, first against diverse views within its own ranks such as Gnosticism, Arianism, and Manichaeism, then against the pagans [literally “the country folk”] who tended to cling to the old ways and who had little to do with these new-fangled notions coming out of the big cities. By taking a deity with easily identifiable features—horns, goat legs, what-have-you—they could more clearly draw the battle lines between the new faith and the old. “We worship the One True God; you worship Satan.”
Most Wiccans I know will answer that question with something like “We don’t believe in Satan. He’s a Christian god.” While a simplistic reply, it’s true. Modern Wiccans worship a wildly diverse bunch of deities, but most tend to focus on the Goddess as a gentle, loving, and nurturing divine-mother figure. Many, but not all, include “the Horned God” as Her consort. Traditional Wiccan groups—Gardnerians, especially—emphasize the balance between male and female and see God and Goddess as equal, or as almost equal but with the Goddess in charge. The Horned God, often named as Cernunnos, is variously seen as the Lord of the Hunt, the Lord of Death*, or the Wild One of the Forest.
[*Footnote: Though “Lord of Death” sounds scary to Christian ears, for most Wiccans death is a necessary part of and balance to life, a door through which we all must pass to enjoy new life. Death is a gift, not a curse.]
Wiccans emphatically are NOT Satan worshippers as they are so often depicted by the news media or Hollywood. Satanism in fact is a perversion of Christianity, a religion which requires Christianity, and a belief in Christian symbols, to exist at all. The symbolism of a satanic rite—the inverted cross, defiling the host, ritually blaspheming God, the Black Mass itself—is all meaningless without Christianity as the prototype, if you see what I mean. Without God, there could be no devil.
And none of that figures in any way in Wicca.
It’s interesting to note that throughout the Old Testament, Satan was really a very minor character. In Job he is pictured as “the accuser,” a kind of prosecuting attorney who “goes to and fro upon the earth” in order to find out if good people are really walking the walk. In Genesis, the tempter is simply “the serpent,” which was a widespread near-Eastern symbol for wisdom and which seems to be a hold-over in the text from far more ancient Sumerian myths. In the OT, God Himself is seen as the source of evil. [I Samuel 19:9; II Chronicles 18:21-22/ 34:24; Proverbs 16:4; Isaiah 19:14/ 63:17; Jeremiah 4:6/ 6:19/ 23:12/ 32:42; Lamentations 3:38; Amos 3:6; Micah 1:12; and others too numerous to mention.]
The idea of a war in heaven and a rebellion of the angels didn’t become popular until much later—Maccabean times [c. 160 BCE] at the earliest, and in some of the Essene writings a century or more later. Some of these teachings obviously influenced early Christian writings. The early church was also strongly shaped by various other religions—notably Mithraism and Zoroasterism—which tended to see the world in terms of a universe-wide war between a god of light and a god of darkness. Some branches of early Christianity, such as the Manicheans, actually took this idea too far, making Satan essentially equal to God in power or, as the Gnostics thought, identified him as the demi-urge/creator of the material world, with the assumption that spirit = good, matter = bad.
Only by the Middle Ages did the devil start to assume his modern appearance—an angelic being who’d revolted against heaven, who is less than God in power, but who still seems to have been granted free rein over his own domain. [A very uncomfortable perch for modern Christianity philosophically: either Satan is not under God’s control, making him equal in power to God, or else God DOES have authority over him, making God responsible for evil.]
Wiccans don’t get involved in this mess at all. The Horned One may be the original model of the Christian devil, but that’s hardly THEIR fault! For Wiccans, the god is most often portrayed as Herne, represented by a stag or as a man with a stag’s antlers. Herne was later mutated by the Romans into Cernunnos, who often had goat’s horns and who represented a more pastoral divinity [i.e. a lord of domestic animals versus lord of wild animals in the woods.] The Greek Pan was seen as having a goat’s horns and legs, and is the most obvious prototype for the Christian devil, especially in some of his more, um, licentious aspects.
Horns, of course, represent the male principle in nature. Many—not all—Wiccans see nothing wrong with celebrating sexuality as a divine gift and even as an expression of worship. This may be one of the biggest and most important schisms between modern Wicca and modern Christianity. Wiccans find nothing immoral, sinful, or evil about sex or the body or sexual pleasure, which puts them in direct opposition to a modern Judeo-Christian culture that is still up tight about such things—especially in puritanical America.
And this is for fundamentalist Christians further proof that Wiccans must be devil-worshippers, since sex is sinful and Satan is the author of sin.
So the long answer is . . . there are indeed superficial similarities between the modern Christian devil and the Wiccan Horned God, yes, but they are due to ignorance, arrogance, and deliberate manipulation by the Christian clerics who demonized [literally!] the nature-based religions of the people they were trying to convert. For our part, Wiccans do NOT worship the devil. He is a Christian god.
Peace!
Bill