Catholic Encyclopedia (1913)/Giulio Carlo de' Toschi di Fagnano
Mathematician, born at Sinigaglia, Italy, 26 September, 1682; died there 18 May, 1766. He made his higher studies at the Collegio Clementino in Rome and there won great distinction, exception in the one subject which has made him famous; in fact his aversion to mathematics was extreme, and it was only after his college course that he took up the study of this branch,but then he did so with such earnestness and ability that, without the help of any teacher, he mastered it from its foundations. Most of his important researches were published in the current numbers of the "Giornale de' Letterati d'Italia". He is best known on account of his investigations on the length and division of arcs of certain curves, especially the lemniscate; this seems also to have been in his own estimation his most important work, since he had the figure of the lemniscate with the inscription: "Multifariam divisa atque dimensa Deo veritatis gloria", engraved on the title-page of his "Produzioni Matematiche", which he published in twovolumes (Pesaro, 1750), and dedicated to Benedict XIV. The same figure and words "Deo veritatis gloria" also appear on his tomb, a testimony to the earnest devotion to science and the deeply practical piety which characterized his entire life; his attachment to the sovereign pontiff was warm and sincere, and of his twelve children one became archdeacon of the cathedral of Sinigaglia and another a Benedictine nun. As a writer he is praised by his contemporaries for his great mildness in controversy, as well as for his clearness and accuracy of thought and diction.
Edward C. Phillips.