Simon Grunau (died ca. 1530) was the author of Preussische Chronik, the first comprehensive history of Prussia. The only personal information available is what he wrote himself in his work: that he was a Dominican priest from Tolkmicko Tolkmicko (Tolkemit) near Frombork (Frauenburg) just north of Elbląg (Elbing) in Poland. He preached in Danzig (Gdańsk) and claimed to have met Pope Leo X and Polish King Sigismund I the Old. The chronicle was written in the German language sometime between 1517 and 1529. Its 24 chapters deal with Prussian landscape, agriculture, inhabitants, their customs, and history from earliest times to up to 1525 when the Protestant Duchy of Prussia was created. It also contains a short (about a hundred words) vocabulary of the Prussian language, one of the very few written artifacts of this extinct language. While often biased and based on dubious sources, this work became very popular and is the principal source of information on Prussian mythology. The chronicle circulated as a frequently copied manuscript and was first published in 1876. Modern historians often dismiss the Preussische Chronik as a work of fiction.
Grunau lived at the time of political division and fierce religious conflicts in Prussia, and as a Catholic priest, was biased against Protestants. In 1525, the Monastic State of the Teutonic Knights was transformed into the Duchy of Prussia, the first Lutheran state in the world.Royal Prussia, under the sovereignty of the Polish Crown, also became largely Lutheran; only the Bishopric of Warmia remained Catholic.