This edition provides access to source material of central significance for an important phase in European politics. It revolves largely around the conquest of the Upper and Rhenish Palatinate, electorship status for Maximilian I of Bavaria, the end of the Spanish-Dutch armistice, the War of the Huguenots in France and the Valtellina conflict. The first volume opens with a lengthy introduction on the pontificate of Gregory XV and also sets out extensive historical, administrative and prosopographic material on the Roman Curia. With its detailed record of written sources and archive material this edition can also claim to be a reference manual on the years 1621-1623.