Campanus of Novara

• Illustration — First page of the Latin edition of Euclid's Elements by Campanus (1482 printing) • Illustration — Tetragonismus idest circuli quadratura, 1503 Campanus wrote a Latin edition of Euclid's Elementa in fifteen books. This work by Campanus was influential and was the most frequently used compilation of Euclid until the 16th century. It was based on a compilation by Robert of Chester and also includes material from: Arithmetica by Jordanus de Nemore, commentary on Euclid by Anaritius, and additions by Campanus himself. It would later become the first printed edition of Euclid, published by Erhard Ratdolt in Venice in 1482 as Preclarissimus liber elementorum Euclidis perspicacissimi. In the field of astronomy, he wrote a Theorica Planetarum in which he geometrically described the motions of the planets as well as their longitude. He also included instructions on building a planetary equatorium as well as its geometrical description. Campanus also attempted to determine the time of each planet's retrograde motion. The data on planets are drawn from the Almagest and the Toledan Tables of the Arab astronomer Arzachel. Campanus gave precise instructions on using the tables, and made detailed calculations of the distances to the planets and their sizes. This work has been called "the first detailed account of the Ptolemaic astronomical system... to be written in the Latin-speaking West." A house system for horoscopes that divides the prime vertical into equal 30° arcs, or houses, is often attributed to him but the method is known to have been described by others before his time.