Libretti that he provided for Handel included those for Giulio Cesare, Ottone, Flavio, Tamerlano, Rodelinda, and several others; for Bononcini, he produced two, Calfurnia and Astianatte.
His career began as a cellist in Italy, and he arrived in London in 1701: he swiftly became master of the 2nd Duke of Bedford's chamber music.
Haym became the teacher and manager of the already successful soprano Joanna Maria Lindehleim negotiating a 100 guinea contract for ten performances in 1706.
However, subsequent editors, beginning with Angelo Geremia, so enlarged the work that it came to be considered a general bibliography of Italian literature.
A much enlarged edition was published in Milan in 1771-72 by Federico Giandonati, and the work was the standard bibliography of Italian literature until the nineteenth century.