Between 1560 and 1593 political and theological struggles over religion took place. The participants in this power game had different confessional standpoints, each claiming to represent pure doctrine, which they elaborated in theological tracts and polemical letters. Archbishop Laurentius Petri played a key role in these disputes. Many considered him to be the mainstay of the Lutheran Reformation. Even after his death, his theological standpoint was generally regarded as normative. In early modern times, the national and international political ambitions and agendas of the Swedish kings were intimately connected with religious policy. The intricate course of events during the sixteenth century cannot be studied thoroughly if the impact of theology is neglected. While the texts that are decisive for an understanding of the early Swedish Reformation period have been printed, most of the sources that could illuminate Swedish church history in the latter part of the sixteenth century have not yet been published. It is the purpose of this project to make the various manuscript sources accessible to research through critical editions together with commentaries and summaries in English