De revolutionibus orbium coelestium have begun work on his new system by that time. Most historians believe that he wrote the "Commentariolus" after his return from Italy, possibly only after 1510. At this time, Copernicus anticipated that he could reconcile the motion of the Earth with the perceived motions of the planets easily, with fewer motions than were necessary in the "Alfonsine Tables", the version of the Ptolemaic system current at the time. In particular, the heliocentric Copernican model made use of the Urdi Lemma developed in the 13th century by Mu'ayyad al-Din al-'Urdi, the first of the Maragha astronomers to develop a non-Ptolemaic
Paris in the 16th century Beginning in 1522, wealthy Parisians loaned their money to the Bureau de Ville, the city government, which in turn made loans to the King. In exchange the King gave the city the right to collect certain taxes in Paris, and the Parisian investors received a healthy eight percent return for their loans to the city. By the second part of the 16th century, however, the Kings were so deeply in debt that wealthy Parisians refused to lend any more money; the King was forced to borrow money from Italian bankers, who received the right to receive a portion of French