to master writing counterpoint in each species before moving on to the next. The species are, in order, note against note; two notes against one; four notes against one; ligature or suspensions (one note against one, but offset by half of the note value); and florid counterpoint, in which the other species are combined freely. Once all the species are mastered in two voices, the species are gone through again in three voices, and then in four voices. (Occasionally, in modern counterpoint textbooks, the third and fourth species are reversed with suspensions being taught before four notes against one.) Fux expressed the intention of adding sections on how to write counterpoint for more than four parts, indicating that rules in this area were to be "less rigorously observed". However, citing his poor health as a result of gout and age, he chose to conclude the book as it stood. Modern counterpoint education is greatly indebted to Gradus ad Parnassum, and Fux presented the ideas with such clarity and focus that both subsequent and modern counterpoint texts continue to cite his work, from the book by Albrechtsberger (Gründliche Anweisung zur Komposition) to 20th century examples such as the book by Knud Jeppesen (Counterpoint: The Polyphonic Vocal Style of the Sixteenth Century). Furthermore, Gradus ad Parnassum is a noteworthy historical document in that it clearly delineates the stylistic distinction of the entire baroque era between an antique and sacred style and a more modern and largely secular style. The Latin edition of Fux's Gradus ad Parnassum from the year 1725 is the only surviving book of J.S. Bach's personal library of theoretical works. As Mizler was a student of J.S. Bach, musicologist Christoph Wolff has suggested that Bach may have played some part in persuading Mizler to translate the treatise. Works In addition to writing Gradus ad Parnassum, Fux also composed numerous sacred and secular works. Fux's compositions were catalogued by Ludwig Ritter von Köchel who also catalogued Mozart's works. Sacred compositions Fux's sacred works include masses (Missa canonica, Missa Corporis Christi,), requiems, oratorios (Santa Dimpna, Infanta d'Irlanda, K 300a (1702) Il fonte della salute, K 293 (1716) ), litanies, Vespers settings, motets, graduals, offertories, Marian antiphons (21 settings of Alma Redemptoris mater, 22 settings of Ave Regina, 9 of Regina coeli, and 17 of Salve regina), settings of the text "Sub Tuum Praesidium", Hymns (many are lost), Sequences, Introits, Communion hymns,