(King James') interest in witchcraft
was not particularly keen until his marriage to the fourteen-year old
Anne of Denmark (1574 – 1619). Although at this time witchcraft was not a
hot topic of discussion in Scotland or England, it was a matter of
intense interest in Denmark and adjacent countries, which were suffering
the throes of an outbreak of witch mania. Witches were being outed by
accusers in every village and hamlet, and the people were terrified of
the Devil’s agents, as witches were understood to be. They had a very
different concept of witchcraft than what we have today. Witches were
looked upon as slaves of Satan, compelled to do his bidding.
Shortly after the marriage, Anne took ship to Scotland to be with her
new husband, but the vessel was beset by foul weather and a series of
mishaps forced it to take shelter in a port on the coast of Norway. When James heard
of the great storm that had driven back Anne’s ship, he embarked on an
uncharacteristic course of action—he sailed from Scotland to Norway to
claim his bride personally. It has been called the only romantic gesture
of his entire life.
His own crossing of the sea was uncommonly stormy. Coupled with the
trouble Anne had encountered in her efforts to reach Scotland, the storm
must have seemed uncanny to the superstitious James. Yet a third storm
struck his ship and almost wrecked the vessel as he was bringing his
bride home to Edinburgh in the spring of 1590. It merely confirmed James
in his conviction that the Danish royal family and nobility, which he
had met with in Kronborg Castle over the Christmas season, had been
correct—witches were working black magic to keep Anne out of Scotland.
At that time many people accused of witchcraft were being burned alive
in Norway and Denmark, and the evils of witches were on everyone’s lips.

It was natural, when accusations were made of witchcraft later that same
year in the little village of North Berwick, Scotland, that James should take a personal interest in the
proceedings. More than a hundred persons were arrested, and many of them subjected to
horrifying tortures to extract confessions to a whole range of crimes,
including treasons against the Scottish crown. James took so great a role in the interrogations of the accused witches
and in their trials that when a Scottish jury acquitted one of the
accused, Barbara Napier, due to lack of evidence, James used his power
as monarch to void their verdict, and ordered her execution.
It was with a considerable fund of practical knowledge gleaned from the
testimonies of the supposed North Berwick witches that in 1597 James
came to write his singular dialogue on witchcraft and the supernatural,
which he titled
Demonology. James wrote the book as a public
service. He genuinely believed at this period in his life that
witchcraft was real, and that it was an unholy scourge that threatened
to destroy all of Christendom unless vigorously combated by godly men
such has himself.
Source: http://www.llewellyn.com/journal/article/2186