The last Prince Archbishop of Salzburg, Hieronymus Colloredo (1732–1812), conducted a correspondence with his brother, Imperial Vice Chancellor Gundaker Colloredo (1731–1807), of which a total of 655 letters have survived. Most of them date from the years 1790 to 1800. In the present edition, the letters are historically and critically processed. Due to the enormous variety of topics in the Colloredo correspondence, its duration and density of tradition, it represents an important contemporary document. Hieronymus Colloredo (1732–1812) was Salzburg's Prince Archbishop between 1772 and 1803. He was in correspondence with his brother, Imperial Vice Chancellor Gundaker Collordo (1731–1807). Most of the 655 letters received come from the years 1790 to 1800. As was customary at the time, the letters were written in French. In the present edition, these letters have now been processed in a historical and critical way. In the first part, the preliminary note to the edition, the protagonists are briefly introduced. This is followed by the edition part. In addition to the transcription of the French letters, there are German-language summaries of the letters. In the footnotes the readers receive biographical sketches of the named persons and other explanations. Finally, in the last part, there is a list of directories and registers. The letters can be used for a variety of historical questions, especially because the brothers corresponded not only on political issues, but also, for example, on family matters. Since they lived in a time of war and radical social upheaval at the end of the 18th century, they also wrote about their feelings, fears and worries about the future. Due to the enormous variety of topics in the Colloredo correspondence, its duration and density of transmission, it represents an important contemporary document.