The Kalmar War of 1611-1613 was the last war in which Denmark-Norway prevailed against Sweden, then under young Gustavus Adolphus who inherited the war from his father. Gustavus Adolphus's defeat against Denmark was the catalyst which set him on the path to remake Sweden into a regional great power.

Professor Michael Fredholm von Essen is an historian and former military analyst who has published extensively on the history, defence strategies, security policies, and energy sector developments of Eurasia. He currently is the Head of Research and Development at IRI, an independent research institute. Educated at Uppsala, Stockholm, and Lund Universities, Michael Fredholm von Essen has lectured, including during conferences and as visiting professor, at numerous institutions and universities around the world. He is the author of a large number of books, articles, and academic papers, including Muscovy's Soldiers: The Emergence of the Russian Army, 1462-1689 (Helion, 2018); Charles XI's War: The Scanian War between Sweden and Denmark, 1675-1679 (Helion, 2018); Transnational Organized Crime and Jihadist Terrorism: Russian-Speaking Networks in Western Europe (Routledge, 2017); Understanding Lone Actor Terrorism: Past Experience, Future Outlook, and Response Strategies (Routledge, 2016); Afghanistan Beyond the Fog of War: Persistent Failure of a Rentier State (NIAS, 2018); Eight Banners and Green Flag: The Army of the Manchu Empire and Qing China, 1600-1850 (Pike and Shot Society, 2009); and a large number of articles on early modern warfare in the Arquebusier, the journal of the Pike and Shot Society.