English summary: Kremsmunster Abbey houses one of the most valuable liturgical vessels of the Early Middle Ages: a lavishly decorated and inscribed Eucharistic chalice, which was donated by the Bavarian duke Tassilo III and his wife Liutpirc, a Longobard princess. Created about 1250 years ago in the Salzburg area, this unique work of art has been surrounded by splendour and mystery for centuries. Scholars regard the Tassilo-Liutpirc chalice as a symbol of the old Bavaria and a short-lived symbiosis of Mediterranean-insular post-antiquity. However, little was known about its creation, authenticity and original function. The message of the mysterious images and ornaments remained a mystery despite many efforts. This volume tries to solve this. As a result of a five-year research project, it is now possible for the first time to present a comprehensive descriptive, photographic and graphic documentation as well as detailed archaeometric and goldsmithing analyses using state-of-the-art technology. The historical environment and the artistic bloom of that time are illuminated against the background of the glorious rule of Tassilo and his scheming overthrow in 788 by Charlemagne. With detective-like meticulousness, the lost art treasures of Tassilo III are brought back to life and the enigmatic image program of the Tassilo Liutpirc chalice is decoded as an allegorical visualization of the celestial city. German description: Zu den herausragendsten Kunstdenkmalern des Alpenraumes gehort der Tassilokelch, der von Baiernherzog Tassilo III. und seiner Frau Liutpirc wohl 777 fur Stift Kremsmunster in Oberosterreich gestiftet wurde. Der Kelch ist namengebend geworden fur Kunst und Ornamentik einer Vielzahl von Goldschmiedearbeiten, vorwiegend aus archaologischen Befunden der 2. Halfte des 8. Jh.