This article accompanies the publication and translation of two messages from king Frederick II of Denmark to king Charles IX of France and to Catherine de' Medici. The former focuses on the bestowing of a knighthood to the Danish monarch and him becoming a knight of the French Order of St Michael and his acceptance of the Order's golden chain. The latter concerns the role of the French crown and its ambassador in Copenhagen, Charles de Danzay, in stabilizing the international situation during the Northern Seven Years' War, and in finding a peaceful compromise between the main adversaries, the Danish and the Swedish kingdoms. The author places both epistolary works in the context of the epoch under study, considering the main stages of Franco -Danish relations in the second half of the fifteenth century - late sixteenth century. The author notes that to the present day, in historiography, there is no integrated concept of description of dynastic, political, and economic contacts between Denmark and France in the Middle Ages and the early modern period (before 1600). This paper partly solves this problem by dividing the history of Franco -Danish contacts into three periods. The first (1456-1519) represents the time of the beginning of diplomatic relations between the French kingdom and the Danish state. The second (1519-1561) consists of a series of bilateral crises and attempts to find a way out of a difficult international situation. The third (1561- 1589) marks the stabilization of Franco -Danish relations and the transformation of friendly communication into an allied partnership. The author concludes that, having undergone a series of crises and difficult periods, the Franco -Danish relations in the second half of the sixteenth century transformed into strong allied ties, which allowed France to maintain its influence in the north of Europe by the beginning of the seventeenth century.