When the Jesuits began to teach mathematics, they adopted the existing European curriculum which included Sacrobosco’s Sphaera.Christoph Clavius, the most influential Jesuit mathematician, published a commentary on the Sphaera in 1570 which was widely used. Its publication also marked a change in publication policy by the Roman Jesuits. As the Jesuits prepared a uniform curriculum for the Society’s schools in the 1580s and 1590s, Clavius offered a comprehensive mathematics curriculum and urged the Society to teach more mathematics and to train more Jesuit mathematicians. But some Jesuit philosophers rejected mathematics as unscientific. The Ratio Studiorum of 1599 included the Sphaera but did not expand Jesuit mathematical education. Jesuits continued to teach the Sphaera and to use Clavius’ commentary until about 1650.