They pop up everywhere, from Hollywood blockbusters to children's television shows, from books to Shakespeare's plays, and Sunday night you'll probably see more than a few of them trick or treating on city streets.

Witches weren't always relegated to a single day in October. They have been with us almost since the beginning, and though they've acquired a less-than-desirable reputation, not all witches were evil.

“We can't really talk about the origins of witchcraft, since it seems to have been with us forever,” said Helen Ostovich, a professor of English and cultural studies and witchcraft expert at McMaster. “In fact, there are mentions of witches and witchcraft in Greek mythology, and in the scriptures of Christianity, Judaism and Islam. I don't think there is a culture in the world without some form of it.”

Throughout history, accusations of practicing witchcraft were often used as tools in neighbourhood or family feuds, or to attack women who were able to gain employment in any of the few jobs open to them.

In 1590 hundreds of accused witches were rounded up in Scotland after King James VI's return from Denmark was delayed due to bad weather, thought to be the work of witchcraft. The infamous Salem witch trials of 17th century colonial Massachusetts saw hundreds of people accused of practicing witchcraft, the hysteria having spread across the Atlantic.

Though generally thought of as a cave-dwelling, haggard old woman brewing potions in a cauldron, the stereotype developed of the oft-maligned sorceress doesn't apply to all those considered witches.

Starting around the 15th century, “cunning folk” began to establish themselves in Britain and throughout Europe. The helpful practitioners of magic were said to be able to locate missing persons or treasure, tell fortunes and, most importantly, combat the evil side of witchcraft, giving us the “good witch/wicked witch” story line used extensively in popular culture. These so-called wise people operated with impunity from persecution until the mid-18th century, when new laws made much of their work illegal.

Despite the laws, witchcraft managed to survive for a short time longer until a combination of things finally drove it to the brink of extinction.

“The rise of newspapers and the information age along with the general acceptance of science meant that witches were no longer taken seriously,” said Ostovich.

Still, aspects of the craft live on in: psychics, palm readers and astrologers all lay claim to the same supposed skills that the witch once did, and children still clamour for brooms, pointy hats and green face paint come Halloween.