Then in 1553, he was offered a position in mathematics at Vienna where he would travel to ultimately decline the appointment, instead relocating to Kraków in 1554 for the next 20 years as a practicing doctor. While there, he continued his work within mathematics and astronomy, further compiling his calculations of trigonomic functions with funding from Emperor Maximilian II with the aid of numerous assistants. The canon of Warmia Georg Donner and the bishop of Warmia Johannes Dantiscus were both patrons of Rheticus. Rheticus was also commissioned to make a staff for king Sigismund II of Poland, while he held a position as teacher in Kraków for many years. From there he went to Košice in the Kingdom of Hungary, where he died. For much of his life, Rheticus displayed a passion for the study of triangles, the branch of mathematics now called trigonometry. In 1542 he had the trigonometric sections of Copernicus' "De revolutionibis" published separately under the title "De lateribus et angulis triangulorum" ("On the Sides and Angles of Triangles"). In 1551 Rheticus produced a tract titled "Canon of the Science of Triangles," the first publication of six-function trigonometric tables (although the word "trigonometry" was not yet coined). This pamphlet was to be an introduction to Rheticus' greatest work, a full set of tables to be used in angular astronomical measurements. At his death, the "Science of Triangles" was still unfinished. However, paralleling his own relationship with Copernicus, Rheticus had acquired a student from Wittenberg who sought him out. Valentinus Otho, devoted to completing his teacher's work, oversaw the hand computation of approximately 100,000 ratios to at least ten decimal places. When completed in 1596, the volume, "Opus palatinum de triangulis," filled nearly 1,500 pages. Its tables were accurate enough to be used in astronomical computation into the early twentieth century. Rheticus narrates the third part of John Banville's 1975 novel "Doctor Copernicus", relating how he convinced Copernicus to publish the book. The novel itself is less about Copernicus's work than about his life and the 16th century world in which he lived. The episode "Claudia" of the U.S. science fiction series "Warehouse 13" referencing a teleportation device in the form of a compass said to have been built by Rheticus.