This book examines the involvement of Denmark in the Thirty Years' War, a watershed in the history of early modern Europe. Not only did the war permanently alter the European balance of power, but the pressures and demands created by such a prolonged and intensive conflict could not help but have a tremendous impact on the governments, societies, and economies of each of the major participants.

Although Denmark, under the leadership of the dynamic King Christian IV (1596-1648) was truly one of Europe's great powers in the early seventeenth century, historians have generally neglected its role in the Thirty Years' War.

Denmark's involvement in the war, however, was of vital importance for the anti-Habsburg cause, and it prevented the complete triumph of Catholic and Habsburg forces in the period between the defeat of the Bohemian rebels and the Elector Palatine in the early 1620s and the intervention of Sweden and France in the early 1630s.

Lockhart emphasized that the effects of the war on Denmark itself were profound, proving to be a major turning point, primarily in terms of the political order. Prior to Christian's intervention, Denmark was a limited monarchy in which the king shared power equally with the landed aristocracy.

Although Denmark was still an elective monarchy when Christian IV died in 1648, the breakdown of the Crown-aristocratic consensus was a necessary precursor to the establishment of absolute monarchy in Denmark in 1660.