Doctoral Dissertations

Date of Award


Degree Type


Degree Name

Doctor of Philosophy



Major Professor

Thomas Burman

Committee Members

Irven Resnick, Michael Kulikowski, Robert Bast, Denise Phillips


“God’s Deaf and Dumb Instruments: Albert the Great’s Speculum Astronomiae and Four Centuries of Readers” is a study of the reception and influence of what is perhaps the most important work dealing with astrology to be produced in the Latin West during the middle ages. In order to determine the impact and importance of the Speculum I have dealt with questions relating to its authorship and dating, while studying its contents in the context of Albert’s larger body of work as well as the readers who found it useful and how they approached the Speculum. I have studied these readers both directly, through a study of thirty-five of the fifty-nine surviving manuscripts, as well as indirectly through a consideration of the way that other writers used the Speculum through the end of the fifteenth century.

In the course of my research I travelled to archives in England, Italy, Switzerland, Germany, and the United States to study codices containing the Speculum, as well as examining microfilm copies of volumes housed in the Ambrosiana collection of Notre Dame University and in the Pope Pius XII Vatican Film Library at St. Louis University. My focus was upon the works that came to be bound with the Speculum and the marginalia readers left behind, as well as the accuracy of individual copies of the text. Furthermore, I have studied the writings of an array of authors, from the thirteenthcentury physician Peter d’Abano, to the fifteenth-century humanist Pico della Mirandola, to determine how these scholars viewed astrology and the place of the Speculum in their writings.

In this way I have been able to demonstrate that astrology was central to the medieval worldview of intellectual elites. The Speculum astronomiae, which I demonstrate was indeed written by Albert the Great around the year 1260, served as an important component of the preservation of the study and practice of astrology as a discipline permissible to Christians. Standing as a semi-canonical defense of the science, physicians, astrologers, natural philosophers, and those interested in doctrinal purity read it with profit, while both defenders and detractors of astrology found it important to address the Speculum in their own work.

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