In 16th-17th century Britain, there was widespread fear of witches and belief in their evil powers. James I wrote a book called Daemonologie in 1597 that reinforced common beliefs about witches. More women than men were accused of witchcraft because women were seen as weak and prone to evil. Shakespeare's Macbeth contains many references that echo popular contemporary ideas about witches, such as flying through the air, collecting ingredients at night for their cauldron brews, and having animal familiars.