He is best known for his invention of the "proportional eight-pointed compass" which has two arms with cursors that allow the solution of problems in measuring the circumference, area and angles of a circle.
In Prague, he also met Michiel Coignet and Giordano Bruno, who used the compass to refute Aristotle's hypothesis on the incommensurability of infinitesimals, thus confirming the existence of the "minimum" which was the basis of his atomic theory.
[2] Bruno published the dialogues Mordentius and De Mordentii circino which praised Mordente, but also presented criticisms that raised protests from the mathematician.
After Mordente gained support in the dispute from the French Charles, Duke of Guise, Bruno was forced to flee Paris.
In 1591 Mordente returned to Italy and entered the service of Alexander Farnese, Duke of Parma, where he published his last mathematical treatise.