The basic course of learning in the Middle Ages was the study of the seven liberal arts: grammar, rhetoric, logic, arithmetic, music, geometry, and astronomy. A renewal of interest in the natural world in the 1200s ensured a prominent place for astronomy in the growing universities of Europe. This collection of scientific theories about the constellations and other scholarly texts was probably compiled as a textbook. The constellations and signs of the zodiac were rendered in a pen-and-ink technique that lends liveliness to the depiction of the positions of the stars in the sky.