Between 1558 and 1721, Sweden, Denmark, Muscovy / Russia, the Polish-Lithuanian Commonwealth, and Prussia-Brandenburg competed for power and influence in a series of wars dubbed "The Northern Wars" by our guest professor Robert Frost. We discuss how these states handled the challenge of new military technology and tactics, growing armies, skyrocketing military spending, and combat against opponents with varying capabilities in different climate and terrain, in in a process called military revolution. It would transform the societies and warfare alike, creating the fiscal-military state, the precursor of modern states. This first of military revolutions is by it is seen by its supporters as an prerequisite for major military and political change ever since.