ABSTRACT
A recurrent theme in early modern Hungarian military, political, and diplomatic correspondence is the use, or improvement, of cryptography and all the entailing problems. These topics are usually covered at the very beginning or end of a letter in a few explicit remarks, and it is mentioned here which cipher worked and which did not, what letters they had sent or received. Such an example can be found in the second sentence of a 1662 letter sent to the Transylvanian politician Mihály Teleki, where his correspondent reported that he had earlier received both the letter and the cipher key. “As to a good-willed lord, I am at your service. An officer handed me your letter together with the clavis a few days ago.” 1
