First collected edition of these texts by the Arab astrologer Masha'Allah ibn Atharī, translated by John of Seville from the Arabic and edited by Joachim Heller, professor of mathematics at Nuremberg. John of Seville was the main translator from Arabic into Castilian together with Dominicus Gundissalinus during the early days of the Toledo School of Translators. His work flourished between 1135 and 1153. "De Revolutione annorum mundi," which had first been published in 1493 in Venice, is divided into 46 chapters and consists of general treatises on time (including a paragraph on the leap-year), the interpretation of different astrological constellations, and climate. It is inserted a chapter headed "Epistola ... de Rebus Eclipsium," the only chapter in the work to touch on astronomy. It is not mentioned on the title and according to the editor Joachim Heller (ca 1518-1590) it was also translated from its original sources by John of Seville. The second book, printed here for the first time, tells of the influence of the stars on man, depending on the sign under which he is born. Book three, "De receptione," which had also been published before in Venice in 1493, is the Latin translation by John of Seville of the horoscopes of Masha'Allah, the sources for which are now lost.