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Mathematical Treasure: Robert Recorde's Castle of Knowledge

Frank J. Swetz (Pennsylvania State University)

The Castle of Knowledge (1556) was Robert Recorde's (1510-1558) last major work. It is a dialogue discussing the celestial sphere and the heliocentric and Ptolemaic theories of the universe. The frontispiece features two characters: Fate and Fortune. Note the symbolism built around them and its significance. Recorde understood and acknowledged the heliocentric theory but still supported the dominant classical system.

An illustration of the Ptolemaic system is given on page 9.

These images are supplied through the courtesy of the Folger Library, Washington, D.C.

Index to Mathematical Treasures

Frank J. Swetz (Pennsylvania State University), "Mathematical Treasure: Robert Recorde's Castle of Knowledge," Convergence (February 2019)