Discus Chronologicus in quo Omnes Imperatores et Reges orbis Europaei.

A chronological disc with 14 rings listing the Roman Emperors (original and Holy), popes, Eastern emperors and sultans, and monarchs of Spain, France, Britain, Denmark, Sweden, Poland, Bohemia, Hungary, Russia, Portugal and Prussia. It starts ad AD 1 and, although the disk marks 1800, the last printed date is the accession of Ulrika Eleonora as Queen of Sweden, but not her abdication in 1720. The names of three Roman emperors of the House of Habsburg-Lorraine have been added in the same hand: Joseph II, (acceded 1765), Leopold II (1790) and Francis II (1792). The previous two emperors have been ignored. The arm is tethered at the centre of the disc and is printed with the titles of each circle. The title is on a banner held aloft by two putti. 

The calendar is taken from the Bequemer Schul- und Reisen-Atlas, also titled Atlas scholasticus et itinerarius by Christoph Weigel. Weigel's well-known travel atlas, published in collaboration with Professor Johann David Köhler, was first printed in Nuremberg in 1718.

Johann David Köhler (January 18, 1684 - March 10, 1755) was a German historian. His academic pursuits were on Roman coins as historical artifacts, ancient weapons and genealogy. Köhler also worked as a university librarian in Altdorf and contributed to the early bibliographical literature.

Christoph Weigel the Elder [1654-1725] was a German goldsmith, engraver, printer and mapmaker. He was initially apprenticed as an engraver in the publishing center of Augsburg, after which he held various positions in Vienna and Frankfurt. In 1698, he became a citizen of the city of Nuremberg and established his own publishing firm there. Weigel is known to have worked closely with the most prominent of the Nuremberg map publishers, Johann Baptist Homann [1663-1724] as well as with his brother, Johann Christoph Weigel [1654 - 1726] and the German academic, Johann David Koehler [1684-1755], the latter in the publication of a number of School atlases. His cartographic output included the Atlas Scholasticus [1712], Bequemer Schul und Reisen Atlas (in association with Koehler) [1724], and the Orbis Antiquus 1724.  Following Weigel's death in 1725, control of the firm passed to his widow, who published many of her late husband's maps and atlases posthumously. The widow Weigel eventually ceded control of the firm to her son, Johann Christoph Weigel the Younger [d.1746], who later went into partnership with Adam Gottlieb Schneider, forming the firm of Schneider-Weigel. Which continued as Nuremberg publishers until the early 19th century.