Francesco Xavierio, a learned Italian writer, was born in the province of Valtellina in 1695, and entered the order of the Jesuits at the age of twenty. His uneasy disposition drove him about from one pursuit to another, before it fixed its attention on any particular subject. He first taught humanity at Padua. Then he studied and taught theology at Bologna. His next vocation was that of a preacher at Venice and Modena. At length he was found once more at Padua engaged in literary labours. It was there that Quadrio undertook the arduous project of writing a History of Poetry under all its different forms in every age and country. At first the execution of the plan went on prosperously. Pope Benedict XIV., and the eminent writer Cordara, cheered him on in his toils. He was indefatigable in rummaging the libraries of Venice, Milan, and Bologna, and in collecting materials from all quarters. He stated his facts and opinions with as much fulness and exactness as could be expected in a work of such a general character. The only part of the subject in which he glaringly failed was that which related to modern foreign languages. In course of time, however, his success began to be seriously impaired. Want of money gave rise to melancholy, and melancholy deranged both mind and body. Nothing but change would solace him. He wandered Quakers restlessly from one European city to another. He threw off the garb of the Jesuits, and appeared as a plain secular priest. His book itself was for a time laid aside. Even after it was resumed, he did not show his former uniting energy. When the work was at length completed, under the title of *Storia e Ragione d'Ogni Poesia*, 7 vols. 4to, Bologna and Milan, 1741–52, it appeared that some portions of the later volumes were mere compilations. Quadrio died at Milan in 1756.