De revolutionibus orbium coelestium De revolutionibus orbium coelestium De revolutionibus orbium coelestium ("On the Revolutions of the Heavenly Spheres") is the seminal work on the heliocentric theory of the Renaissance astronomer Nicolaus Copernicus (1473–1543). The book, first printed in 1543 in Nuremberg, Holy Roman Empire, offered an alternative model of the universe to Ptolemy's geocentric system, which had been widely accepted since ancient times. Copernicus initially outlined his system in a short, untitled, anonymous manuscript that he distributed to several friends, referred to as the "Commentariolus". A physician's library list dating to 1514 includes a manuscript whose description matches the "Commentariolus", so Copernicus must
Christianity in the 16th century the Reformed church in Geneva, which became an "unofficial capital" of Reformed Christianity in the second half of the 16th century. He exerted a remarkable amount of authority in the city and over the city council, such that he has (rather ignominiously) been called a "Protestant pope." Calvin established an eldership together with a consistory, where pastors and the elders established matters of religious discipline for the Genevan population. Calvin's theology is best known for his doctrine of (double) predestination, which held that God had, from all eternity, providentially foreordained who would be saved (the elect) and likewise who would