This edition contains the official correspondence of the papal nuncios at the court of the Emperor from January 1577 to August 1578, i.e., the reports of the nuncios Giovanni Delfino and Bartolomeo Portia and the instructions from Gregory XIII's secretary responsible for the foreign policy of the curia, Cardinal Tolomeo Gallio. In this period the Holy See made a determined effort to strengthen the Counter-Reformation in the Empire and the Hapsburg-ruled countries with the assistance of the new Emperor, Rudolph II. While through its local representatives the curia was able to score some successes in the territories immediately subject to Rudolph II (banishment of Protestant preachers, reduction of religious privileges for estates of the realm), its impact on the Empire itself was limited, as is shown by such things as the problem of obedience or that of the award of regalia.