15th century

Algorithmus Linealis Numeratione[m]

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One of the earliest treatises on calculation by the aid of counters on an abacus. In the dedication, Heinrich Stromer von Auerbach (1482-1542) refers to Aristotle and Boethius. There is a brief introduction on the use of counters or projectiles, then the work covers addition, subtraction, duplication, mediation, multiplication, division, progression, and the rule of three.

Georgii Trapezuntii In Claudii Ptolemaei Centum Aphorismos Commentarius

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A collection of notable works relating to astrology dealing with body condition, the soul, luck and accidents, and various medical topics all dealt with in terms of their relationship to the stars. The commentator, George Trebizond, a celebrated scholar, became professor of Greek at Venice around 1430 and was later appointed secretary to Pope Eugenius. He wrote numerouos commentaries and translated many Greek books into Latin.