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Mathematical Treasure: Epitome of the Almagest

Frank J. Swetz (The Pennsylvania State University)

The first Latin edition of Ptolemy’s Almagest appeared in 1450. The translator and commentator of this work was the Greek scholar and humanist, George of Trebizond (1395-1472). He had hoped that his friend Georg Peuerbach (1423-1461) would publish a more usable abridgement of the work. Peuerbach died before he finished the task but assigned its completion to his former student Regiomontanus [Johannes Müller] (1436-1476). Regiomontanus completed the abridgment, Epitome of the Almagest, within four years; however, it was not published until 1496. The title page appears below:


In the copy examined here, the back of the title page contains notes and diagrams appended by a reader from the distant past:

A front illustration shows Regiomontanus conferring with Ptolemy under a model of the earth:

This volume is annotated throughout with copious marginal notes. In the image below, see the small added drawing of a hand, labeled “noto”, marking an important point in the text:

Spherical geometry is considered later in the text:

The images above were obtained through the courtesy of the Dibner Library of Science and Technology, Smithsonian Libraries.

For images from another copy of this book, see Mathematical Treasure: Peuerbach’s and Regiomontanus’s Ptolemy. For images from another edition of the Almagest, see Mathematical Treasure: Ptolemy’s Almagest.

Editor’s note: For more information about George of Trebizond, Peuerbach, and Regiomontanus, see Regiomontanus: Defensio Theonis [contra Trapezuntium, or Defense of Theon against George of Trebizond]. The Defense was a separate work from the Epitome, never published but surviving in manuscript, in which Regiomontanus challenged George’s understanding of Ptolemy’s Almagest and of astronomy in general.

Index to Mathematical Treasures

Frank J. Swetz (The Pennsylvania State University), "Mathematical Treasure: Epitome of the Almagest," Convergence (May 2017)