This dissertation deals with, magic, popular beliefs in the Witches Sabbath (in Sweden called Blåkulla), the witchcraft trials within the jurisdiction of Svea Circuit Court 1597–1720 and some aspects of the Great Northern Witch Craze of 1668–1677. The study examines the meanings of popular beliefs (folklore) in magic and Blåkulla and the actions, causes and events that actualised these beliefs. The thesis also deals with how people thought in the 17th century, how magic was thought to be operative, the accusations that were made, how and for what purposes and in which contexts magic was used, popular beliefs about Blåkulla, how people protected themselves from witches and witchcraft, witchcraft accusations and honour, how accusations were used to destroy another persons honour, social conflicts, other emotions and actions (such as envy) and causes of events that resulted in accusations, who was accused, who made an accusation, why more women than men were accused, the legal framework, evidence, how the court worked and reasoned, and the sentences imposed. The dissertation also examines the Witchcraft Craze of 1668–1677 and deals with aspects such as the great wave of rumours concerning witchcraft i.e. that the witches were taking small children and teenagers to the Witches Sabbath, how the trials spread throughout the country and the hysteria that haunted some areas inthe north of Sweden.