As a confessional document, the Book of Concord was successful due to its precise definitions. Its authors believed they possessed true understanding of Luther's legacy and needed to protect against variation. Establishing the limits of a singular Lutheran Church, Jakob Andreae and his colleagues achieved considerable cohesion among many Protestant Princes of Germany. As a political statement, however, the Book of Concord represented the failure of Gnesio-Lutherans to consider the repercussions of their actions. Rather than establish pan-Protestant agreement, it further deepened divides and created a watershed for the future. At the international level, the Book and its champions eschewed Protestant solidarity to oppose Catholicism, preferring to rely solely on the Peace of Augsburg. In England, concern mounted that Augustus, Elector of Saxony and the most powerful Imperial Prince, proved firmly opposed to theological moderation and political cooperation. Even so, Elizabeth maintained through other avenues a solid set of allies vital during the following decade.

The early and mid-1580s were hardly dull. The Cologne War demonstrated volatility in the lower Rhineland in 1583; William of Orange's assassination brought further crises to the nascent United Provinces in 1584; and soon afterwards the death of François, Duke of Anjou, left the French royal succession to the Huguenot guardian, Henri of Navarre.