Giovanni Antonio Magini (1555 – 1617) was an Italian astronomer, astrologer, cartographer, and mathematician. In 1588, he was chosen over Galileo to be the Chair of Mathematics at the University of Bologna. Magini supported a geocentric system of the world, in preference to Copernicus’ heliocentric system, and he devised his own planetary theory of eleven rotating spheres.

In his De Planis Triangulis (1592), he described the use of quadrants in surveying and astronomy. In 1592, Magini published Tabula Tetragonica, and in 1606 devised extremely accurate trigonometric tables. He also worked on the geometry of the sphere and applications of trigonometry, for which he invented calculating devices. In addition, he published his theory of concave spherical mirrors and a commentary on Ptolemy’s Geographia.

As a cartographer, his life’s work was the preparation of Italia, or, Atlante Geografico d’Italia (Geographic Atlas of Italy), printed posthumously by Magini’s son in 1620. This was intended to include maps of every Italian region with exact nomenclature and historical notes. Its production, begun in 1594, was expensive and Magini assumed various additional posts in order to fund it, including tutor in mathematics to the sons of Vincenzo I of Gonzaga, Duke of Mantua, a major patron of the arts and sciences. He also served as Court Astrologer. The Duke of Mantua, to whom the atlas is dedicated, assisted him with this project and allowed for maps of the various states of Italy to be brought to Magini, as he did not design the maps himself. The governments of Messina and Genoa also assisted Magini financially in this project.